FORM 2
THE PA TENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
TITLE OF THE INVENTION
"DECARBONYLATION OF ALDEHYDES"
APPLICANT
Indian Institute of Technology, Bombay of Powai, Mumbai-400076, Maharastra, India; Indian
INVENTORS Prof. Debabrata Maiti, Atanu Modak and Arghya Deb all Indian Nationals of Indian Institute of Technology, Bombay Powai, Mumbai 400 076, Maharashtra, India
The following specification particularly describes the invention and the manner in which it is to be performed

FIELD OF THE INVENTION:
The present invention relates to a method for the preparation of decarbonylated product of a wide range of aldehydes. The products are prepared in efficient, straight forward transformations where an aldehyde and transition metal catalyst are combined in the presence of air, under conditions wherein the transition metal catalyst catalyzes the formation of decarbonylated product from the aldehyde. The method of the instant invention can also be employed for one-pot oxidation/decarbonylation of alcohols.
BACK GROUND OF THE INVENTION:
Methods for removal of carbonyl groups from organic molecules are immensely important in synthesis including in the total syntheses of natural products and in biology. Biological systems oxygenate aldehydes to generate formate and alka(e)ne. Synthetic deformylation reactions occurs usually via rapid oxidative addition into the C(0)-H bond and subsequent rate determining extrusion of CO. Synthetically, the utility of functional groups is mainly due to their ability to act as directing groups as well as high reactivity and selectivity in a wide variety of transformations. In this regard, metal mediated decarbonylation reaction has attracted attention of chemists for decades since such processes enable temporary use of the beneficial features of-CHO functionality. Also the majority of C-C bond cleavage reactions catalyzed by cytochromes P450 (CYPs) in Nature are decarbonylation of aldehydes. Interestingly, biosynthesis of alka(e)ne from cyanobacteria has been recently suggested to occur via decarbonylation as one of the key steps. Furthermore, selective conversion of carbohydrate (fatty aldehyde) to fuel grade alkane could be an attractive alternative to existing expensive hydrogenation methodologies.

The aldehyde decarbonylation reactions were first discovered by Tsuji and Ohno using a stoichiometric amount of Wilkinson's complex, RhCl(PPh3)3. Later Doughty and Pignolet discovered that diphosphines ligated Rh-complexes were much more reactive as catalysts. Since then, diphosphine chelated rhodium have been widely used in decarbonylation reactions of aldehydes. In 2008, Madsen and coworkers reported detailed mechanistic studies on decarbonylation of aldehydes catalyzed by bidentate phosphine ligated rhodium complex. Other metals such as Pd- and Ru- as well as Ir- complexes were also investigated as catalysts for decarbonylation and related reactions.
Although some of these catalysts are commercially available, a majority of them suffers from high cost, limited substrate scope, harsh/impractical reaction conditions. Often, the efficient catalytic (or even stoichiometric) decarbonylation are done under elevated reaction temperatures (typically >160°C) or with a chemical scavenger (e.g. di-phenylphosphoryl azide) to remove the evolved CO. In total synthesis, a stoichiometric (not catalytic) amount of Rh-catalyst is often employed for crucial decarbonylations of aldehyde functionalities.
Thus, there remains a need for an efficient catalytic process for high-efficiency removal of carbonyl group from aldehydes and afford high yields of the respective decarbonylation products. It would therefore be highly desirable to provide a process which facilitates an efficient catalytic decarbonylation of aldehydes circumventing the aforesaid drawbacks of the prior art processes.
Accordingly, the inventors of the present invention have endeavored to provide a rapid and robust method for decarbonylation of aldehydes which overcomes the aforesaid problems associated with the prior art processes. Also, the method afforded by the present invention requires a simple work-up procedure and is therefore economical, efficient and easily scalable.

OBJECTIVE OF THE INVENTION:
The objective of the present invention is thus to afford the catalytic decarbonylation of aldehydes under (i) mild conditions (ii) broader substrate scope (iii) without a chemical scavenger for CO and (iv) by a process that is both economic and scalable.
A further object of the present invention is to provide the catalytic decarbonylation of aldehydes employing a simple palladium based catalysts. Pd(OAc)2 was found to be a highly active decarbonylation agent without the employment of an exogenous ligand.
Since palladium/carbon monoxide interaction is weaker compared to previously used metals such as Ru, Rh, Ir etc for decarbonylation, a carbon monoxide scavenger was not necessary for the present invention.
Another object of the present invention is to provide the process of decarbonylation, which is preferably carried out in the presence of cyclohexane or dichloroethane (DCE) as a solvent at about 130 C to 140 C and without a chemical scavenger of CO.
Furthermore, microwave assisted decarbonylation of aldehyde can also be carried out within 50 min at 150 C in ethyl acetate.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration only, because various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1. Absorbance spectra in Soret and visible regions for met-Mb (Fe 3+), deoxy-Mb (Fe2+) and Mb-CO complex (Fe2+).

Figure 2. Absorbance spectra in visible and near infrared regions for met-Mb (Fe 3+), deoxy- Mb (Fe2+) and Mb-CO complex.
DETAILED DESCRIPTION OF THE INVENTION:
In describing and claiming the invention, the following terminology will be used in accordance with the definitions set forth below. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. As used herein, each of the following terms has the meaning associated with it in this section. Specific and preferred values listed below for individual process parameters, substituents, and ranges are for illustration only; they do not exclude other defined values or other values falling within the preferred defined ranges.
As used herein, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise.
The terms "preferred" and "preferably" refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.
When the term "about" is used in describing a value or an endpoint of a range, the disclosure should be understood to include both the specific value or end-point referred to.
As used herein the terms "comprises", "comprising", "includes", "including", "containing", "characterized by", "having" or any other variation thereof, are intended to cover a non-exclusive inclusion.
"Decarbonylation" is herein defined as process of removal of a carbonyl group from a molecule, usually as carbon monoxide.

"Aldehyde" refers to any of a class of organic compounds, in which a carbon atom shares a double bond with an oxygen atom, a single bond with a hydrogen atom, and a single bond with another atom or group of atoms (generally designated as R). The group without R is called the aldehyde group or formyl group. The double bond between the carbon and oxygen is characteristic of all aldehydes and is known as the carbonyl group. The carbon atoms bonded to the carbonyl group of an aldehyde may be part of saturated or unsaturated alkyl groups or they may be alicylic, aromatic or heterocyclic rings. The present invention can be extended to the decarbonylation of any aldehyde. Preferably, however the aldehyde is an aromatic aldehyde.
The representative aldehydes with varying "R" groups bonded to the aldehyde group (-CHO) that can be efficiently decarbonylated employing the process of the present invention are tabulated in Table 1.
The present invention pertains to a process for decarbonylation of aldehydes (R-CHO) comprising contacting the aldehyde with a solvent selected from the group comprising cyclohexane or dichloroethane in the presence of a palladium catalyst under conditions that promote the catalyst to catalyze decarbonylation of the aldehyde to yield a decarbonylated product. Ethyl acetate is found as the best solvent to carry out decarbonylation reaction under microwave condition.
Another aspect of the invention relates to a process for one-pot oxidation and decarbonylation of alcohol (R-OH) comprising contacting the alcohol with a solvent selected from the group comprising cyclohexane or dichloroethane in the presence of a palladium catalyst, under conditions that promote oxidation of the alcohol to the corresponding aldehyde and subsequent decarbonylation of the aldehyde to yield a corresponding decarbonylated product.
Table 1

Entry Representative aldehyde

Palladium has been found to provide a particular advantageous selective decarbonylation of representative aldehyde compounds. Suitable palladium catalysts for use in the present invention include but are not limited to Pd(OAc)2, Pd{acac)2, Pd(CF3C02)2, PdCl2(CH3CN)2, Pd(2,4-pentadiene), Pd(dba)2, Pd2(dba)3.
The palladium is provided in the decarbonylation reaction mixture is present in a catalytic amount effective to decarbonylate the representative aldehyde under optimal reaction conditions. Suitable concentration of the catalyst is in the range of 5 mol % to 16 mol %.

Preferably the concentration is about 5 mol% to 8 mol% and most preferably about 8 mol%.
The palladium catalyst employed in the process of the present invention is preferably supported on one of the primary supports known in the art. Suitable catalyst supports include alumina, silica, carbon, barium sulphate, calcium carbonate, diatomaceous earth etc.
The methods for producing a palladium catalyst are many and varied and well known to the art. Any of these methods except as otherwise indicated herein, may be used to prepare the catalyst used in the invention.
The process conditions of the decarbonylation reaction can vary widely. Typically, the temperature can vary widely from about 100 C to 500 C. Preferably, the temperature is about 100 C to 200 C, more preferably about 100 C to 150 C and most preferably about 130°Ctol40°C.
According to a significant aspect of the invention, a suitable solvent is employed for the decarbonylation reaction. Non-limiting examples of such exemplary solvents include cyclohexane, dichloroethane and the like. As will be appreciated by a person skilled in art the decarbonylation reaction can be performed in unpurified (as received) Cyclohexane or DCE an in air (or N2) with equal efficiency.
The invention is further illustrated by the following numbered examples. Features of certain of the processes of this invention are described herein in the context of one or more specific embodiments that combine various such features together. The scope of the invention is not, however, limited by the description of only certain features within any specific embodiment, and the invention also includes (1) a subcombination of fewer than all of the features of the described embodiment, which subcombination may be characterized by the absence of the features omitted to form the subcombination. (2) Each of the features, individually included within the combination of any described embodiment, (3) other combinations of features formed by grouping only selected

features taken from two or more described embodiments, optionally together with other features as disclosed elsewhere herein. Some of the specific embodiments of the processes thereof are as follows
EXAMPLE 1:
Pd-catalyzed decarbonylation of various aldehydes (isolated yield)
The decarbonylation of a representative aldehyde employing the optimized process parameters of the present invention has been depicted as follows. Detailed experimental optimization conditions are outlined in Table 4-12.

The Pd-catalysed dcarbonylation of various aldehydes was conducted as schematically depicted above and the isolated yields obtained for each of the various representative aldehydes are tabulated in Table 2. Detailed descriptions of decarbonylation experimental process of each of the individual aldehydes are given in Example 20.
Table 2

Entry Representative aldehyde Isolated yield3

aUnless otherwise stated, all reaction were carried out in 8 mol% catalyst loading with respect to substrate, b5 mol% catalyst loading with respect to substrate, cyield determined by gas chromatography due to low boiling point of the product, using naphthalene as internal standard, d16 mol% catalyst loading with respect to substrate,
After initial experimentation, naphthalene was generated from 2-naphthaldehyde by Pd-catalyzed method. Pd(OAc)2 was selected for optimization with different solvent (Table 1). In the presence of a catalytic amount of Pd(OAc)2 (5 mol% with respect to Pd), the decarbonylation product, naphthalene, was obtained in 96% yield (Table 4, entry 1). However, the catalytic activity dropped when the reaction was carried out in other solvents (Table 4). Note that DCE can also be suitable solvent for this decarbonylation reaction. A number of palladium sources were tried for decarbonylation, among them Pd(OAc)2 in cyclohexane solvent gave best result (Table 5, entry 1). Decarbonylation

with or without base (K2CO3) gave similar result (Table 6, entry 2, 1). This decarbonylation reaction can be performed in unpurified (as received) cyclohexane (or DCE) and under air (or N2), with equal efficiency (Table 9, entry 1, 2).
EXAMPLE 2:
Palladium catalyzed oxidation/decarbonylation of alcohols
One-pot oxidation/decarbonylation of alcohols was conducted employing the decarbonylation conditions as depicted as follows. Under these reaction conditions, alcohols are first oxidized to aldehyde and (b) then decarbonylation reaction takes place. Detailed experimental optimization conditions are outlined in Table 14-16.

The palladium catalyzed oxidation/decarbonylation of various alcohols was conducted as schematically depicted above and the yields obtained for each of the various representative alcohols by gas chromatography are tabulated in Table 3. Detailed descriptions of oxidation/decarbonylation experimental process of each of the individual cases are given in Example 21.
Table 3

Entry Representative alcohol GC yield3


Unless otherwise stated, all reaction were carried out in 8 mol% catalyst loading with respect to substrate, 12 mol% catalyst loading with respect to substrate
EXAMPLE 3:
Palladium catalyzed microwave assisted decarbonylation of aldehyde
Optimized condition of microwave assisted decarbonylation of aldehyde is depicted as follows. Detailed experimental optimization conditions are outlined in Table 20-22.

The palladium catalyzed microwave assisted decarbonylation of various aldehyde was conducted as schematically depicted above and the isolated yields obtained for each of the various representative aldehydes are tabulated in Table 4. Detailed descriptions of oxidation/decarbonylation experimental process of each of the individual aldehydes are given in Example 22.
Table 4

Entry Representative alcohol Isolated yield


EXAMPLE 4:
Optimization Experiments by varying solvent for decarbonylation of aldehyde

Table 5

Entry Solvent GC Yield (%)
1 Cyclohexane 96
2 Dichloroethane(DCE) 95
3 Dimethoxyethane(DME) 79
4 2-Methyltetrahydrofiiran 74
5 2-Methyl-2-butanol 75
6 Tetrahydropyran(THP) 76
7 Dioxane 49
8 Me3CCN 55
9 PhCF3 52
10 Bu20 36
11 C6H6 68
12 Methylcyclohexane 65

13 m-Xylene 29
14 Toluene 37
15 Butyronitrile 76
16 NMP 74
17 Anisole 65
18 PhCN 62
19 DMF 50
20 DMA 49
21 DIPEA 38
EXAMPLE 5:
Optimization by varying Pd-source and solvent for decarbonylation of aldehyde

Table 6

Entry Pd source Solvent GC Yield (%)
1 Pd(OAc)2 Cyclohexane 75
2 Pd(CF3C02)2 Cyclohexane 71
3 Pd(dba)2 Cyclohexane 68
4 Pd(acac)2 Cyclohexane 71
5 Pd(OAc)2 DCE 54
6 Pd(CF3C02)2 DCE 64
7 Pd(dba)2 DCE 55
EXAMPLE 6:
Optimization by varying solvent and base (type and amount) for decarbonylation of aldehyde


Table 7

Entry Base Amount (mmol) Solvent GC Yield (%)
1 K2C03 1.0 Cyclohexane 76
2 — Cyclohexane 77
3 Cs2C03 1.0 Cyclohexane 23
4 NaOAc 1.0 Cyclohexane 53
5 K3PO4 1.0 Cyclohexane 44
6 K2CO3 1.0 DCE 33
7 NaOAc 1.0 DCE 56
8 K2CO3 0.4 Cyclohexane 50
9 Cs2C03 0.4 Cyclohexane 33
10 NaOAc 0.4 Cyclohexane 78
11 K3PO4 0.4 Cyclohexane 48
EXAMPLE 7:
Optimization by varying Pd-source, base and solvent for decarbonylation of aldehyde

Table 8

Entry Pd source Base Solvent GC Yield (%)
1 Pd(OAc)2 K2C03 Cyclohexane 99
2 Pd(OAc)2 K3PO4 Cyclohexane 92
3 Pd(OAc)2 CS2CO3 Cyclohexane 55
4 Pd(OAc)2 NaO'Bu Cyclohexane 69
5 Pd(acac)2 - Cyclohexane 80
6 Pd(CF3C02)2 - Cyclohexane 69
7 Pd(2,4-pentadiene) - Cyclohexane 76
8 PdCl2(CH3CN)2 - Cyclohexane 7

9 Pd(acac)2 DCE 70
10 Pd(CF3C02)2 DCE 79
11 Pd(2,4-pentadiene) DCE 53
12 Pd(dba)2 DCE 73
13 Pd2(dba)3 DCE 78
EXAMPLE 8:
Optimization by varying amount of molecular sieves for decarbonylation of aldehyde

Table 9

Entry Amount of Molecular sieves (mg) GC Yield (%)
1
2 3 4 0
50
100
200 56 84 82 96
EXAMPLE 9:
Optimization of reaction atmosphere and necessity of base for decarbonylation of aldehyde


Table 10

Entry Reaction condition GC Yield (%)
1 Under air 100
2 Under N2 92
3 With base 88
4 Without base 100
EXAMPLE 10:
Optimization of ligand for decarboxylation of aldehyde

Table 11



Table 12

EXAMPLE 11:
Effect of scavengers in decarbonylation of aldehyde


Table 13

Entry Condition GC Yield (%)
1
2 3 Without Scavengers
With AIBN
With TEMPO 86% 63% 23%
EXAMPLE 12:
Optimization experiments by varying solvent for oxidation/decarbonylation of alcohols

Table 14

Entry Solvent GC Yield (%)
1 Cyclohexane 71
2 DCE 67
3 MeCN 25
4 DMF 22
5 Dioxane 3
6 TFT 54
EXAMPLE 13:
Optimization experiment by varying base for oxidation/decarbonylation of alcohols

Table 15

Entry Base GC Yield (%)
1 - 56
2 Pyridine 51
3 KO'Bu 19
4 K2C03 53

Table 16

Entry Base GC Yield (%)
1 - 59
2 Pyridine 40
3 Et3N 19
EXAMPLE 14:
Optimization of reaction atmosphere for oxidation/decarbonylation of alcohols

Table 17

Entry Substrate Reaction Condition GC Yield (%)
1
2
3 R = CH3
R = CH3
= N02
R = CH3 Under Nitrogen Under Air
Under Oxygen 39
97 52 100

= N02 79
EXAMPLE 15:
Optimization of amount of molecular sieves for oxidation/decarbonylation of alcohols

Table 18

Entry Amount of Molecular sieves (mg) GC Yield (%)
1
2 75 150 34 59
EXAMPLE 16:
Optimization of amount of palladium catalyst for oxidation/decarbonylation of alcohols

Table 19

Entry Amount of catalyst (mol%) GC Yield (%)
1 2 8
12 56 88

EXAMPLE 17:
Optimization by varying solvent, temperature and time for microwave assisted decarbonylation of aldehyde

Table 20

Entry Solvent Temp. (°C) Time (min) GC yield (%)
1 Cyclohexane 80 10 0
2 Cyclohexane 100 20 0
3 Cyclohexane 120 30 0
4 Cyclohexane 140 20 0
5 Cyclohexane 140 30 Not significant
6 Cyclohexane 140 40 Not significant
7 Cyclohexane 140 50 42
8 DMF 100 5 0
9 DMF 150 10 0
10 DMF 180 20 0
11 DMF 140 50 5
EXAMPLE 18
Optimization by varying solvent for microwave assisted decarbonylation of aldehyde

Table 21

Entry Solvent GC Yield (%)
1 Dichloroethane 5

2 m-Xylene 2
3 Acetonitrile 7
4 Toluene 60
5 Cyclohexane 42
6 2-Methyl THF 100
7 THF 100
8 Ethyl acetate 100
9 Anisole 0
10 DMF 5
11 Nitrobenzene 0
12 Ethylbenzene 3
13 1,4-Dioxane 1
14 2-Methoxy ethanol 34
EXAMPLE 19
Optimization by varying amount of catalyst, temperature and time for microwave assisted decarbonylation of aldehyde

Table 22

Entry Pd(OAc)2 x mol% Temp. (°C) Time (min) GC Yield (%)
1 5 140 50 78
2 5 150 40 43
3 5 150 50 75
4 6 140 50 83
5 6 150 40 63
6 6 150 50 85
7 7 140 50 92
8 7 150 40 75
9 7 150 50 100
10 8 140 50 100
11 8 150 40 92
12 8 150 50 100

EXAMPLE 20:
Experimental procedure for decarbonylation of aldehyde.
General Procedure A for deformylation of aldehydes with 5-16 mol% palladium
catalyst loading (with K2CO3 / without K2CO3) under air
A clean, oven-dried screw cap schlenk reaction tube with previously placed magnetic stir-bar was charged with molecular sieves (4A, 150 mg), K2CO3 (104 mg, 0.75 mmol),* aldehyde (0.5 mmol), palladium acetate (5-16 mol%). Cyclohexane (1.3 mL) was added to this mixture by syringe. The tube was tightly closed by screw cap and placed in a preheated oil bath at 140°C. The reaction mixture was vigorously stirred for 24 h. The reaction mixture was cooled to room temperature and filtered through funnel. Reaction tube and residue was washed with ethyl acetate (20 mL) and water (4 mL) was added to the filtrate. Organic layer was collected with the help of separating funnel. Aqueous part was extracted twice more with ethyl acetate (10 mL) while saturating aqueous part with NaCl. Combined organic part was dried over anhydrous Na2SC>4. The filtrate was concentrated and resulting deformylated product was purified via column chromatography using silica gel and pet ether/ ethyl acetate as eluate. *For without base reaction the addition of K2C03 was omitted.
General Procedure B for deformylation of aldehydes with 5-16 mol% palladium catalyst loading (with K2CO3 / without K2CO3) under nitrogen
A clean, oven-dried screw cap schlenk reaction tube with previously placed magnetic stir-bar was charged with molecular sieves (4A, 150 mg), K2CO3 (104 mg, 0.75 mmol),* aldehyde (0.5 mmol), palladium acetate (5-16 mo\%). The tube was then evacuated and back-filled with nitrogen. The evacuation/backfill sequence was repeated two additional times. Under a counter flow of nitrogen, remaining liquid reagents were added, followed by cyclohexane (1.3 mL) by syringe. The tube was tightly closed by screw cap and placed in a preheated oil bath at 140°C. The reaction mixture was vigorously stirred for 24 h. The reaction mixture was cooled to room temperature and filtered through funnel. Reaction tube and residue was washed with ethyl acetate (20 mL) and water (4 mL) was added to the filtrate. Organic layer was separated with the help of separating funnel.

Aqueous part was extracted twice more with ethyl acetate (10 mL) while saturating aqueous part with NaCl. Combined organic part was dried over anhydrous Na2SO4. The filtrate was concentrated and resulting deformylated product was purified via column chromatography using silica gel and pet ether, ethyl acetate as eluate. *For without base reaction the addition of K2CO3 was omitted.
Pyrene-4-carbaldehyde (Table 2, entry 1). Deformylation was done by general procedure A with pyrene-4-carbaldehyde (0.5 mmol, 115 mg) and 5 mol% palladium acetate (0.025 mmol, 6 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline pyrene was eluted by pet ether only. Isolated Yield 95% (96 mg). 1H NMR (400 MHz, CDC13) 5: 8.18 (d, 4H, J= 7.7), 8.08 (s, 4H), 8.00 (t, 2H, J = 7.7).

Anthracene-9-aIdehyde (Table 2, entry 2). Deformylation was done by general procedure A with anthracene-9-aldehyde (0.5 mmol, 104 mg) and 8 mol% palladium acetate (0.04 mmol, 9mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline anthracene was eluted by pet ether only. Isolated Yield 97% (86 mg). %). LH NMR (400 MHz, CDCI3) 5: 8.42(s, 2H), 8.02-7.98 (m, 4H), 7.48-7.44 (m, 4H).


Phenanthrene-9-aldehyde (Table 2, entry 3). Deformylation was done by general procedure A with phenanthrene-9-aldehyde (0.5 mmol, 104 mg) and 5 mol% palladium acetate (0.025 mmol, 6mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 100-200). White crystalline phenanthrene was eluted by pet ether only. Isolated Yield 94% (84 mg). 'H NMR (400 MHz, CDC13) 5: 8.69 (d, 2H, J= 8.1), 7.89 (dd, 2H, J= 7.8, 1.4), 7.74 (s, 2H), 7.68-7.57 (m,4H).

l-Napthaldehyde (Table 2, entry 4). Deformylation was done by general procedure A with l-Napthaldehyde (0.5 mmol, 78 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline napthalene was eluted by pet ether only. Isolated Yield 92% (59 mg). 'H NMR (400 MHz, CDC13) 6: 7.86-7.82 (m, 4H), 7.50-7.46 (m, 4H).

2-NapthaIdehyde (Table 2, entry 5). Deformylation was done by general procedure A with 2-napthaldehyde (0.5 mmol, 78 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline napthalene was eluted by pet ether only. Isolated Yield 82% (52 mg). !H NMR (400 MHz, CDCI3) 5: 7.86-7.82 (m, 4H), 7.50-7.46 (m, 4H).


4-Methylbenzaldehyde (Table 2, entry 6). Deformylation was done by general procedure A with 4-methylbenzaldehyde (0.5 mmol, 60 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 100%.

2,4,6-Trimethylbenzaldehyde (Table 2, entry 7). Deformylation was done by general procedure A with 2,4,6-trimethylbenzaldehyde (0.5 mmol, 74 mg) and 16 mol% palladium acetate (0.08 mmol, 18 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 100%.

(E)-4-Styrylbenzaldehyde (Table 2, entry 8). Deformylation was done by general procedure A with (E)-4-styrylbenzaldehyde (0,5 mmol, 104 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline product was eluted by pet ether only. Isolated Yield 94% (84 mg). ]H NMR (400 MHz, CDC13) 5: 7.53-7.50 (m, 4H), 7.38-7.34 (m, 4H), 7.28-7.24 (m, 2H), 7.1 l(s, 2H).


4-((lE,3E)-4-PhenyIbuta-l,3-dienyl)benzaldehyde (Table 2, entry 9). Deformylation was done by general procedure A with 4-((lE,3E)-4-phenylbuta-l,3-dienyl)benzaldehyde (0.25 mmol, 59 mg) and 8 mol% palladium acetate (0.02 mmol, 5 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline product was eluted by pet ether only. Isolated Yield 64% (33 mg). Recovered starting materials 27% (16 mg). [H NMR (400 MHz, CDC13) 5: 7.45-7.42 (m, 4H), 7.35-7.31 (m, 4H), 7.25-7.21 (m, 2H), 6.96 (dd, 2H, J= 11.9,2.9), 6.67 (dd, 2H, J= 11.9,2.9).

2-Methoxybenzaldehyde (Table 2, entry 10). Deformylation was done by general procedure A with 2-methoxybenzaldehyde (0.5 mmol, 68 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Colourless liquid anisole was eluted by pet ether only. Isolated Yield 81% (44 mg). *H NMR (400 MHz, CDC13) 5: 7.31-7.25 (m, 2H), 6.96-6.88 (m, 3H), 3.79 (s, 3H). 13C NMR (100 MHz, CDC13) 8: 159.69, 129.60, 120.80, 114.03, 55.26.


3,4,5-Trimethoxybenzaldehyde (Table 2, entry 11). Deformylation was done by general procedure A with 3,4,5-trimethoxybenzaldehyde (0.5 mmol, 98 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White solid product was eluted by pet ether - ethyl acetate mixture (98:2 v/v). Isolated Yield 68% (57 mg). 'H NMR (400 MHz, CDC13) 5: 7.00 (t, 1H, J = 8.4), 6.58 (d, 2H,), 3.81 (t, 2H, J - 8.4), 3.86 (s, 6H), 3.85 (s, 3H). I3C NMR (100 MHz, CDCI3) 5: 153.65, 338.15,123.82, 105.26, 60.99, 56.19 .

4-Nitrobenzaldehyde (Table 2, entry 12). Deformylation was done by general procedure A with 4-nitrobenzaldehyde (0.5 mmol, 76 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Yellow liquid nitrobenzene was eluted by pet ether only. Isolated Yield 80% (49 mg). 'H NMR (400 MHz, CDC13) 8: 8.25-8.22 (m, 2H), 7.71 (tt, 1H, J = 7.4, 1.2), 7.58-7.53 (m, 2H).


4-FormyIbenzonitrile (Table 2, entry 13). Deformylation was done by general procedure A with 4-formylbenzonitrile (0.5 mmol, 66 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Yellow liquid benzdnitrile was eluted by pet ether only. Isolated Yield 70% (36 mg). 'H NMR (400 MHz, CDC13) 8: 7.67-7.64 (m, 2H), 7.61 (it, 1H, J = 7.5, 1.4), 7.50-7.45 (m, 2H).

4-Chlorobenzaldehyde (Table 2, entry 14). Deformylation was done by general procedure A with 4-chlorobenzaldehyde (0.5 mmol, 70 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 74%.

4-Bromobenzaldehyde (Table 2, entry 15). Deformylation was done by general procedure A with 4-bromobenzaldehyde (0.5 mmol, 93 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was

determined by gas chromatography using naphthalene as internal standard. GC Yield 28%.

4-Hydroxybenzaldehyde (Table 2, entry 16). Deformylation was done by general procedure A with 4-hydroxybenzaldehyde (0.5 mmol, 61 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White solid product was eluted by pet ether - ethyl acetate mixture (95:5 v/v). Isolated Yield 64% (30 mg).

4-Formylbenzoic acid (Table 2, entry 17). Deformylation was done by general procedure A with 4-formylbenzoic acid (0.5 mmol, 75 mg) and 5 mol% palladium acetate (0.025 mmol, 6 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White solid benzoic acid was eluted by pet ether - ethyl acetate mixture (9:1 v/v). Isolated Yield 85% (52 mg).). !H NMR (400 MHz, CDC13) 5: 8.14-8.11 (m, 2H), 7.62 (tt, 1H, J = 7.4, 1.3), 7.50-7.46 (m, 2H). 13C NMR (100 MHz, CDC13) 5: 171.78, 133.97, 130.39,129.44, 128.68.


Methyl 4-formyIbenzoate (Table 2, entry 18). Deformylation was done by general procedure A with methyl 4-formylbenzoate (0.5 mmol, 82 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Colorless liquid methyl benzoate was eluted by pet ether only. Isolated Yield 74% (50 mg). ]H NMR (400 MHz, CDC13) 5: 8.05-8.02 (m, 2H), 7.54 (tt, 1H, J = 7.4, 1.3), 7.45-7.40 (m, 2H), 3.90 (s, 3H). 13C NMR (100 MHz, CDC13) 8: 167.23, 133.03, 130.27, 129.68,128.47, 52.20 .

Methyl 4-acetyIbenzaldehyde (Table 2, entry 19). Deformylation was done by general procedure A with methyl 4-acetylbenzaldehyde (0.5 mmol, 74 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Colorless liquid acetophenone was eluted by pet ether only. Isolated Yield 80% (48 mg). (H NMR (400 MHz, CDC13) 8: 7.96-7.94 (m, 2H), 7.55 (tt, 1H, J - 7.3, 1.5), 7.47-7.43 (m, 2H), 2.59 (s, 3H). 13C NMR (100 MHz, CDCI3) 8: 198.26,137.17, 133.20, 128.65, 128.38,26.68 .

3-Nitrobenzaldehyde (Table 2, entry 20). Deformylation was done by general procedure A with 3-nitrobenzaldehyde (0.5 mmol, 76 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Yellow liquid nitrobenzene was eluted by pet ether only. Isolated Yield 70% (43

mg). 1H NMR (400 MHz, CDC13) 5: 8.25-8.22 (m, 2H), 7.71 (tt, 1H, J = 7.4, 1.2), 7.58-7.53 (m, 2H).

3-Formylbenzonitrile (Table 2, entry 21). Deformylation was done by general procedure A with 3-formylbenzonitrile (0.5 mmol, 66 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Colorless liquid benzonitrile was eluted by pet ether only. Isolated Yield 73% (37 mg). 'H NMR (400 MHz, CDC13) 5: 7.71-7.65 (m, 2H), 7.61 (tt, 1H, J = 7.6, 1.4), 7.51-7.45 (m, 2H).

3-Vinylbenzaldehyde (Table 2, entry 22). Deformylation was done by general procedure A with 3-vinylbenzaldehyde (0.5 mmol, 66 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 54%.

2-HydroxybenzaIdehyde (Table 2, entry 23). Deformylation was done by general procedure A with 2-hydroxybenzaldehyde (0.5 mmol, 61 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Yield was

determined by gas chromatography using naphthalene as internal standard. GC Yield 94%.

2-Hydroxy-3-methoxybenzaldehyde (Table 2, entry 24). Deformylation was done by general procedure A with 3-formylbenzonitrile (0.5 mmol, 76 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Solid 2-methoxyphenol was eluted by pet ether only. Isolated Yield 73% (37 mg).

Furan-2-carbaldehyde (Table 2, entry 25). Deformylation was done by general procedure A with furan-2-carbaldehyde (0.5 mmol, 48 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 100%.

Thiophene-2-carbaldehyde (Table 2, entry 26). Deformylation was done by general procedure A with thiophene-2-carbaldehyde (0.5 mmol, 56 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 55%.


lH-Pyrrole-2-carbaIdehyde (Table 2, entry 27). Deformylation was done by general procedure A with lH-pyrrole-2-carbaldehyde (0.5 mmol, 48 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 58%.

Thiophene-3-carbaldehyde (Table 2, entry 28). Deformylation was done by general procedure A with thiophene-3-carbaldehyde (0.5 mmol, 56 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 55%.

Isonicotinaldehyde (Table 2, entry 29). Deformylation was done by general procedure A with isonicotinaldehyde (0.5 mmol, 54 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 83%.

Nicotinaldehyde (Table 2, entry 30). Deformylation was done by general procedure A with nicotinaldehyde (0.5 mmol, 54 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 80%.


Picolinaldehyde (Table 2, entry 31). Deformylation was done by general procedure A with picolinaldehyde (0.5 mmol, 54 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 53%.

Quinoline-4-carbaIdehyde (Table 2, entry 32). Deformylation was done by general procedure A with quinoline-4-carbaldehyde (0.5 mmol, 78 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Yellow liquid quinoline was eluted by pet ether - ethyl acetate mixture (92:8 v/v). Isolated Yield 85% (55 mg). 1H NMR (400 MHz, CDC13) 5: 8.91 (dd, 1H, J = 4.2, 1.7), 8.15-8.11 (m, 2H), 7.80 (dd, 1H, J = 8.1,1.2), 7.73-7.69 (m, 1H), 7.55-7.51 (m, 1H), 7.38 (dd, 1H, J = 8.3, 4.2). 13C NMR (100 MHz, CDCI3) 8: 150.43, 148.27, 136.19, 129.56, 129.44, 128.35, 127.87, 126.63, 121.15 .

4-Oxo-4H-chromene-3-carbaldehyde (Table 2, entry 33). Deformylation was done by general procedure A with 4-oxo-4H-chromene-3-carbaldehyde (0.5 mmol, 87 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Yellow solid 4H-chromen-4-one was eluted by pet ether - ethyl acetate mixture (95:5 v/v). Isolated Yield 87% (64 mg). 1H NMR (400 MHz, CDCI3) 8: 8.21 (dd, 1H, J = 8.0, 1.6), 7.86 (d, 1H, J = 6.0), 7.70-7.65 (m, 1H), 7.47-7.39 (m, 2H),

6.35 (d, 1H, J = 6.0). ]3C NMR (100 MHz, CDC13) 5: 177.86, 156.67, 155.51, 133.96, 125.96,125.43, 125.02, 118.34, 113.13 .

lH-Indole-3-carbaldehyde (Table 2, entry 34). Deformylation was done by general procedure A with lH-indole-3-carbaldehyde (0.25 mmol, 36 mg) and 8 mol% palladium acetate (0.02 mmol, 5 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline solid lH-indole was eluted by pet ether - ethyl acetate mixture (98:2 v/v). Isolated Yield 81% (29 mg).). !H NMR (400 MHz, CDC13) 5: 8.15 (s, 1H), 7.68-7.66 (m, 1H), 7.42-7.40 (m, 1H), 7.23-7.15 (m, 2H), 7.19-7.12 (m, 1H), 6.58-6.57 (m, 1H).

5-methoxy-lH-indole-3-carbaldehyde (Table 2, entry 35). Deformylation was done by general procedure A with 5-methoxy-lH-indole-3-carbaldehyde (0.5 mmol, 88 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline solid 5-methoxy-lH-indole was eluted by pet ether only. Isolated Yield 75% (55 mg).).


3-Methyl-l-phenyl-lH-pyrazole-4-carbaldehyde (Table 2, entry 36). Deformylation was done by general procedure A with 3 -methyl-1 -phenyl-1 H-pyrazole-4-carbaldehyde (0.5 mmol, 93 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Colorless liquid 3-Methyl-l-phenyl-lH-pyrazole was eluted by pet ether - ethyl acetate mixture (99:1 v/v). Isolated Yield 66% (52 mg).). 'H NMR (400 MHz, CDC13) 5: 7.78 (d, 1H, J = 2.2), 7.64-7.62 (m, 2H), 7.41-7.38 (m, 2H), 7.24-7.20 (m, 2H), 7.19-7.12 (m, 1H), 6.22 (d, 1H, J = 2.2), 2.37 (s,3H). 13CNMR(100MHz,CDCl3)5: 150.62,140.30,129.45, 127.45, 126.00,118.89, 107.62,13.84.

Dibenzo[b,d]furan-4-carbaldehyde (Table 2, entry 37). Deformylation was done by general procedure A with dibenzo[b,d]furan-4-carbaldehyde (0.5 mmol, 98 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline dibenzo[b,d]furan was eluted by pet ether only. Isolated Yield 89% (75 mg). !H NMR (400 MHz, CDCI3) 5: 7.96-7.94 (m, 2H), 7.58-7.55 (m, 2H), 7.47-7.43 (m, 2H), 7.35-7.31 (m, 2H). 13C NMR (100 MHz, CDC13) 5: 156.35, 127.30,124.39, 122.86, 120.82, 111.84,

Benzo[b]thiophene-3-carbaldehyde (Table 2, entry 38). Deformylation was done by general procedure A with benzo[b]thiophene-3-carbaldehyde (0.5 mmol, 81 mg) and 16 mol% palladium acetate (0.08 mmol, 18 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel

column (mesh 60-120). Colorless liquid benzo[b]thiophene was eluted by pet ether only. Isolated Yield 66% (44 mg). 'H NMR (400 MHz, CDC13) 8: 7.87-7.84 (m, 1H), 7.81-7.78 (m, 1H), 7.40 (d, 1H, J = 5.5), 7.36-7.29 (m, 3H). 13C NMR (100 MHz, CDC13) 6: 139.84,139.72, 126.45, 124.35, 124.30, 123.99, 123.76, 123.63 .

Trans-cinnamaldehyde (Table 2, entry 39). Deformylation was done by general procedure A with trans-cinnamaldehyde (0.5 mmol, 66 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Colorless liquid styrene was eluted by pet ether only. Isolated Yield 74% (40 mg). ]HNMR (400 MHz, CDC13) 5: 7.42-7.39 (m, 2H), 7.32-7.30 (m, 2H), 7.14-7.08 (m, 1H), 6.72 (dd, 1H, J = 17.6, 10.8), 5.72 (dd, 1H, J = 17.6, 0.9), 5.24 (dd, 1H, J = 10.8, 0.9).

(E)-3-(2-Nitrophenyl)acrylaldehyde (Table 2, entry 40). Deformylation was done by general procedure A with (E)-3-(2-nitrophenyl)acrylaldehyde (0.5 mmol, 82 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Yellow colored liquid l-nitro-2-vinylbenzene was eluted by pet ether only. Isolated Yield 84% (57 mg). 13C NMR (100 MHz, CDC13) 5: 147.99, 133.51, 133.30,132.63,128.66,128. 51,124.57,119.14 .


(E)-2-Methyl-3-phenylacrylaldehyde (Table 2, entry 41). Defoimylation was done by general procedure A with (E)-2-methyl-3-phenylacrylaldehyde (0.5 mmol, 73 nig) and 8 mol%'palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Colorless liquid prop-1-enylbenzene (cis : trans -1:1) was eluted by pet ether only. Isolated Yield 59% (35 mg). 1H NMR (400 MHz, CDC13) 8: 7.35-7.27 (m, 4H), 5.26-7.17 (m, 1H), 6.45-6.37 (m, 1H), 5.83-5.74 (m, 1H), 1.90 (dd, 3H, J = 1.8).

3,3-DiphenyIacryIaldehyde (Table 2, entry 42). Deformylation was done by general procedure A with 3,3-diphenylacrylaldehyde (0.5 mmol, 104 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was carried out with base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). Yellow liquid solid ethene-1,1 -diyldibenzene was eluted by pet ether only. Isolated Yield 92% (82 mg). [H NMR (400 MHz, CDC13) 8: 7.36-7.27 (m, 10H), 5.44 (s,2H). BC NMR (100 MHz, CDC13) 6: 150.19, 141.63, 128.43, 128.33, 127.88,114.49.

2,4-Diphenylbut-2-enal (Table 2, entry 43). Deformylation was done by general procedure A with 2,4-diphenylbut-2-enal (0.25 mmol, 55 mg) and 8 mol% palladium acetate (0.02 mmol, 5 mg) loading. Reaction was done without base. Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline solid prop-l-ene-I,3-diyldibenzene was eluted by pet ether only. Isolated Yield 64% (31mg).


Retinal (Table 2, entry 44). Deformylation was done by general procedure B with
retinal (0.5 mmol, 142 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading.
Reaction was done without base. Pure deformylated product was isolated by column
chromatography through a silica gel column (mesh 60-120). Yellow liquid 2-
((lE,3E,5E)-3,7-dimethylocta-l,3,5,7-tetraenyl)-l,3,3-trimethylcyclohex-l-ene was
eluted by pet ether only. Isolated Yield 70% (80 mg).

Heptanal (Table 2, entry 45). Deformylation was done by general procedure B with heptanal (0.5 mmol, 57 mg) and 16 mol% palladium acetate (0.08 mmol, 18mg) loading. Reaction was done without base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 74%.

3-Phenylpropanal (Table 2, entry 46). Deformylation was done by general procedure B with 3-phenylpropanal (0.5 mmol, 67 mg) and 16 mol% palladium acetate (0.08 mmol, 18 mg) loading. Reaction was done without base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 62%.


Citral (Table 2, entry 47). Deformylation was done by general procedure B with citral (0.5 mmol, 76 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Reaction was done without base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 93%.

2-Oxo-2-phenyIacetaldehyde hydrate (Table 2, entry 48). Deformylation was done by general procedure A with 2-oxo-2-phenylacetaldehyde hydrate (0.5 mmol, 67 mg) and 16 mol% palladium acetate (0.04 mmol, 18 mg) loading. Reaction was done without base. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 96%.

EXAMPLE 21:
Experimental procedure for oxidation/decarbonylation of alcohols.
General Procedure C for oxidation/decarbonylation of alcohols with (8-12) mol%
palladium catalyst loading under oxygen
A clean, oven-dried screw cap schlenk reaction tube with previously placed magnetic stir-bar was charged with molecular sieves (4A, 150 mg), benzyl alcohol (0.5 mmol), palladium acetate (8 mol%). The tube was then evacuated and back-filled with oxygen. The evacuation/backfill sequence was repeated two additional times. Under a counter flow of oxygen, remaining liquid reagents were added, followed by cyclohexane (1.3 mL) by syringe. The tube was tightly closed by screw cap and placed in a preheated oil bath at 140 °C. The reaction mixture was vigorously stirred for 24 h. The reaction mixture was cooled to room temperature and yield was determined by gas chromatography using naphthalene as internal standard.

p-Tolylmethanol (Table 3, entry 1). The oxidation/decarbonylation reaction was done by general procedure C with p-tolylmethanol (0.5 mmol, 62 mg) and 8 mol% palladium acetate (0.04 mmol, 9 mg) loading. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 100%.

(4-Nitrophenyi)methanol (Table 3, entry 2). The oxidation/decarbonylation reaction was done by general procedure C with (4-nitrophenyl)methanol (0.25 mmol, 38 mg) and 12 mol% palladium acetate (0.03 mmol, 6 mg) loading. Yield was determined by gas chromatography using naphthalene as internal standard. GC Yield 88%.

EXAMPLE 22:
Experimental procedure for microwave assisted decarbonylation of aldehyde. General Procedure D for microwave assisted decarbonylation of aldehydes with 7 mol% palladium catalyst loading
A clean, oven-dried microwave reaction tube with previously placed magnetic stir-bar was charged with molecular sieves ( 4A, 75 mg), K2C03 (25 mg, 0,18 mmol), aldehyde (0.12 mmol), palladium acetate ( 7 mol%, 0.0084 mmol, 1.9 mg). Ethyl acetate (2.5 mL) was added to this mixture by syringe. The tube was tightly closed by designated cap and placed inside the microwave instrument (Instrument Name: CHM Discover; Method: Dynamic; Temperature; 150 °C; Time: 50 min; Prestirring: 30 sec; Power setpoint: 250;

Pressure setpoint: 250; Power max: On; Stirring: High). After that reaction mixture was cooled to room temperature and filtered through funnel. Reaction tube and residue was washed with ethyl acetate (20 mL) and water (4 mL) was added to the filtrate. Organic layer was separated by separating funnel. Aqueous part was extracted twice more with ethyl acetate (10 mL) while saturating aqueous part with NaCl. Combined organic part was dried over anhydrous Na2S04. The filtrate was concentrated and resulting deformylated product was purified via column chromatography using silica gel and pet ether, ethyl acetate as eluate.

5-methoxy-lH-indole-3-carbaldehyde. Deformylation was done by general procedure D with 5-methoxy-lH-indole-3-carbaldehyde (0.12 mmol, 21 mg). Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline solid 5-methoxy-lH-indole was eluted by EtOAc:pet ether (1:49) only. Isolated Yield 90% (16 mg).

3,4,5-TrimethoxybenzaIdehyde. Deformylation was done by general procedure D with 3,4,5-trimethoxybenzaldehyde (0.12 mmol, 23.5 mg). Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White solid product was eluted by pet ether - ethyl acetate mixture (98:2 v/v). Isolated Yield 65%(13mg).


Dibenzo[b,d]furan-4-carbaldehyde. Deformylation was done by general procedure D with dibenzo[b,d]furan-4-carbaldehyde (0.12 mmol, 23.5 mg). Pure deformylated product was isolated by column chromatography through a silica gel column (mesh 60-120). White crystalline dibenzo[b,d]furan was eluted by pet ether only. Isolated Yield 100% (22 mg).
MECHANISTIC STUDY: EXAMPLE 23:
Detection of carbon monoxide:
1. Generation of carbon monoxide from the aldehyde

A clean, oven-dried screw cap schlenk reaction tube with previously placed magnetic stir-bar was charged with molecular sieves (4A, 225 mg), palladium acetate (8 mol%, 27 mg). The tube was then evacuated and back-filled with nitrogen. The evacuation/backfill sequence was repeated two additional times. Under a counter flow of nitrogen, 1-naphthaldehyde (1.5 mmol, 234 mg, 204 uL) was added, followed by cyclohexane (3 ml) by syringe. The tube was tightly closed by screw cap and placed in a preheated oil bath at 140 X. The reaction mixture was vigorously stirred for 24 h. The reaction mixture was cooled to room temperature and then from the closed reaction tube produced gas was taken out using a Hamilton 5 mL gas syringe.
2. Preparation of deoxygenated myoglobin (Fe 3+) solution
In a two-necked round bottom flask met-myoglobin (Fe ) was taken then 10 ml of distilled water was added. Two necks were closed with septa and a take-off. Then the solution was degassed by cooling to -78 °C (dry ice/ acetone) and allowed to return to room temperature. This sequence is repeated for additional two more times. Then after allowing it to return to room temperature a ballon filled with nitrogen is attached for

nitrogen purging. Absorbance spectra of this solution in Soret region showed peak at 408 nm. Aqueous solution of Na2S2O4 was added to this myoglobin solution using syringe to reduce Fe 3+ to Fe 2+. Absorbence spectra of this solution in Soret region showed peak at 434 nm. It is the characteristic peak of Myoglobin (Fe2+) complex.
3. Preparation of myoglobin (Fe 2+)-CO complex
Gas taken from the reaction tube in a Hamilton gas syringe was purged into the aqueous myoglobin (Fe 2+) solution. Absorbance spectra of this solution showed peak at 423 nm in Soret region and also the peaks at 542 nm and 578 nm. These are the characteristic peaks of myoglobin (Fe )-CO complex.
A person skilled in the art will be able to practice the present invention in view of the description presented in this document, which is to be taken as a whole. Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, one of skill in the art will appreciate that certain changes and modifications may be practiced within the scope of the appended claims. Numerous details and examples have been set forth in order to provide a more thorough understanding of the invention. While the invention has been disclosed in its preferred form, the specific embodiments and examples thereof as disclosed and illustrated herein are not to be considered in a limiting sense. It should be readily apparent to those skilled in the art in view of the present description that the invention can be modified in numerous ways. The inventor regards the subject matter of the invention to include all combinations and sub-combinations of the various elements, features, functions and/or properties disclosed herein.

WE CLAIM
1. A process for decarbonylation of aldehydes (R-CHO) comprising contacting the aldehyde with a solvent selected from the group comprising cyclohexane or dichloroethane in the presence of a palladium catalyst, optionally a base, under conditions that promote the catalyst to catalyze the decarbonylation of the aldehyde to yield a corresponding decarbonylated product.
2. The process as claimed in claim 1, wherein the palladium catalyst is selected from the group comprising Pd(OAc)2, Pd(acac)2, Pd(CF3C02)2, PdCl2(CH3CN)2, Pd(2,4-pentadiene), Pd(dba)2, Pd2(dba)3.
3. The process as claimed in claim 1, wherein the amount of the palladium catalyst is in the range of 5 mol% to 16 mol%.
4. The process as claimed in claim 1, wherein the reaction is carried out at a temperature in the range of 120 °C to 150 °C.
5. The process as claimed in claim 1, wherein the reaction is carried out for at least 8 hours.
6. The process as claimed in any of the claims 1-6, wherein the yield of the decarbonylated product is at least 62%.
7. The process as claimed in claim 1, wherein the aldehyde is selected from any one of the compound tabulated in table 1.
8. A process for one-pot oxidation and decarbonylation of alcohol (R-OH) comprising contacting the alcohol with a solvent selected from the group comprising cyclohexane or dichloroethane in the presence of a palladium catalyst, under conditions that promote oxidation of the alcohol to the corresponding aldehyde and subsequent decarbonylation of the aldehyde to yield a corresponding decarbonylated product.

9. The process as claimed in claim 8, wherein the palladium catalyst is selected from the group comprising Pd(OAc)2, Pd(acac)2, Pd(CF3C02)2, PdCl2(CH3CN)2, Pd(2,4-pentadiene), Pd(dba)2, Pd2(dba)3.
10. The process as claimed in claim 8, wherein the amount of the palladium catalyst is in the range of 5 mol% to 16 mol%.
11. The process as claimed in claim 8, wherein the reaction is carried out at a temperature in the range of 120°C to 150°C.
12. The process as claimed in claim 8, wherein the reaction is carried out for at least 8 hours.
13. A process for microwave assisted decarbonyation of aldehyde comprising contacting the aldehyde with ethyl acetate in the presence of a palladium catalyst, under conditions that promote the catalyst to catalyze the decarbonylation of the aldehyde to yield a corresponding decarbonylated product.
14. The process as claimed in claim 13, wherein the amount of the palladium catalyst is 7 mol%.
15. The process as claimed in claim 13, wherein the reaction is carried out at 150°C.
16. The process as claimed in claim 13, wherein the reaction is carried out for at least 50 min.