Palladium catalysis carbonylation

The a-arylation of carbonyl compounds (sometimes in enantioselective version) such as ketones,107-115 amides,114 115 lactones,116 azlactones,117 malonates,118 piperidinones,119,120 cyanoesters,121,122 nitriles,125,124 sul-fones, trimethylsilyl enolates, nitroalkanes, esters, amino acids, or acids has been reported using palladium catalysis. The asymmetric vinylation of ketone enolates has been developed with palladium complexes bearing electron-rich chiral monodentate ligands.155... 

Lin and Yamamoto described a Pd-catalyzed carbonylation of benzyl alcohols [131]. Thus, under the agency of palladium catalysis and promotion by HI, 3-thiophenemethanol was carbonylated to give 3-thiopheneacetic acid as a major product along with methylthiophene as a minor one. 

The three-component synthesis of benzo and naphthofuran-2(3H)-ones from the corresponding aromatic alcohol (phenols or naphthols) with aldehydes and CO (5 bar) can be performed under palladium catalysis (Scheme 16) [59,60]. The mechanism involves consecutive Friedel-Crafts-type aromatic alkylation and carbonylation of an intermediate benzylpalla-dium species. The presence of acidic cocatalysts such as TFA and electron-donating substituents in ortho-position (no reaction with benzyl alcohol ) proved beneficial for both reaction steps. 

It is reported that the palladium-catalysed intramolecular aromatization of 1,1 -dichloro-9/T-fluoren-9-yIidene (15) may lead to the formation of fullerene fragments.89 The amiulation reaction, under palladium catalysis, between iodoanflines and ketones may yield indole derivatives.90 There have also been studies of the palladium-catalysed carbonylation of o-iodophenols with allenes which may lead to l-benzopyran-4-one derivatives,91 of the intramolecular coupling of phenols with aryl halides,92 and of the intramolecular Heck aiylation of cyclic enamides.93... 

Synthetic methods for the preparation of dienes and enynes abound, yet the use of alkenyl iodonium salts offers distinct advantages. Their coupling reactions with electron-deficient alkenes and alkenyl- or alkynylstannanes constitute a valuable extension to the previously existing methodology, because of mild conditions, ease of operation, high stereoselectivity and good yields. The simplest reaction of this category is with unsaturated carbonyl compounds and requires palladium catalysis. 

The iodyl group (I02) is a good nucleofugue. Under mild conditions, the conversion of several iodylarenes into benzoic acids was realized in good yields, via carbonylation. Carbon monoxide was used at atmospheric pressure and 40-50°C, in aqueous sodium carbonate, with palladium catalysis [9] ... 

The scope of vinyl metals as sources of nucleophilic vinyl groups is very great. As well as the expected electrophiles such as halogens, alkyl and acyl halides, aldehydes and ketones, unsaturated carbonyl compounds and epoxides, they also combine with aryl and alkenyl halides with palladium catalysis. The usual stereochemical course is retention at the vinyl group. It is necessary to decide whether the vinyl metal is reactive enough or whether it must first be transformed into an ate complex. Since most of these vinyl metals can be converted into each other with retention, this is an unusually versatile group of reagents. 

In a very useful modification, simple ketones with CH2 adjacent to the carbonyl (cyclic ketones work much better than acyclic ketones) and ortfto-iodo-arylamines react under palladium catalysis to give indoles directly. The use of dimethylformamide as solvent and DABCO as the base are crucial to the success of the route. Mechanistically, the sequence certainly proceeds through the enamine. As well as being conceptually and practically simple, this method tolerates functional groups that would be sensitive to the acid of the traditional Fischer sequence. This method can also be applied to aldehydes, thus providing a direct route to 2-unsubstituted indoles, including side-chain-protected tryptophans. ... 

Cassar, L., M. Foa, and A. Gardano, The Use of Phase Transfer Catalysis in Palladium-Catalyzed Carbonylation of Organic Halides, J. Organomet. Chem, 121, C55 (1976). 

Aryl-, alkenyl- and alkynylpalladium species readily undergo carbonylation reactions because carbon monoxide as a loosely bonded ligand can reversibly insert into any palladium-carbon bond [110]. Thus, 2-allyl-l-iodocyclopentene (148), under palladium catalysis, reacts with carbon monoxide in two modes, depending on the excess of carbon monoxide and the catalyst cocktail (Scheme 3-39) [110a]. With a slight excess (1.1 atm of CO) in the presence of [Pd(PPh3)4] in tetrahydrofuran, 148 cyclized with one CO insertion to yield 3-methylenebicyclo[3.3.0]oct-l(5)-en-2-one (152), and under 40 atm of CO with [Pd(PPh ,)2Cl2] in benzene/acetonitrile/methanol, methyl 2- 3 -(2 -oxobicyclo[3.3.0]oct-1 (5 )-enyl) acetate 149 after two CO insertions (Scheme 3-39). 

Biaryl structures are found in a wide range of important compounds, including natural products and organic functional materials [8,80,81]. One of the most common and useful methods for preparing biaryls is the palladium-catalyzed coupling of aryl halides with arylmetals (Scheme 1, mechanism A). On the other hand, aryl halides have been known to couple directly with aromatic compounds as formal nucleophiles under palladium catalysis. While the intramolecular cases are particularly effective, certain functionalized aromatic compounds such as phenols and aromatic carbonyl compounds, as well as... 

Diazoalkane carbonylation using palladium catalysis gives unobserved acylketenes, which are captured in situ with nucleophiles (Scheme 7.43). The reactions are suggested to involve palladium complexed ketenes and are carried out with various substrates and nucleophiles. 

B.ii.e Carbonylation and Acylation. The keto function in pyrrolo[3,2-c]pyridin-4-ones and pyrido[3,4- ]pyrrolizidin-l-ones can be enolized and triflated to yield the substrates 72 and 73, respectively (Scheme 34). Replacement of the triflyloxy group by carbonylation is effected with palladium catalysis. Reaction of the pyrido[3,4-fc]-pyrrolizidin-l-ones 73 was complicated by formation of a by-product, namely, the 2-methoxy adduct 74. In the latter case competitive palladium-assisted elimination of the triflyloxy group leads to an imminium intermediate, which adds a methoxy group as a... 

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