Diaryl ketone carbon monoxide

Carbon monoxide rapidly inserts into the carbon—zirconium bond of alkyl- and alkenyl-zirconocene chlorides at low temperature with retention of configuration at carbon to give acylzirconocene chlorides 17 (Scheme 3.5). Acylzirconocene chlorides have found utility in synthesis, as described elsewhere in this volume [17]. Lewis acid catalyzed additions to enones, aldehydes, and imines, yielding a-keto allylic alcohols, a-hydroxy ketones, and a-amino ketones, respectively [18], and palladium-catalyzed addition to alkyl/aryl halides and a,[5-ynones [19] are examples. The acyl complex 18 formed by the insertion of carbon monoxide into dialkyl, alkylaryl, or diaryl zirconocenes may rearrange to a r 2-ketone complex 19 either thermally (particularly when R1 = R2 = Ph) or on addition of a Lewis acid [5,20,21]. The rearrangement proceeds through the less stable... 

When the aryl-aryl coupling was carried out under a carbon monoxide atmosphere in N,N-dimethylimidazolidinone (DMI), carbonylative coupling took place to give unsymmetrical diaryl ketones [Eq.(22)] 120]. 

Carbon monoxide diverts the coupling of diaryliodonium salts and arylboronic acids to the generation of diaryl ketones. Additive carbonylation leading to P-substituted butenolides is observed when propargylic alcohols and diaryl chalcogenides are subjected to the carbonylation conditions. 

As indicated with a strong electron-withdrawing group such as CF3, the reaction gave lower yields of products. When the coupling reaction of aryl(aIkyl)difluoro-silanes and aryl iodides is carried out under an atmospheric pressure of carbon monoxide, unsymmetrical fluorinated diaryl ketones were obtained (refs. 35, 36) ... 

Under some conditions, diaryl ketones are formed in moderate yield from aryl-mercuric salts and carbon monoxide with a palladium salt catalyst °>. 

Suzuki coupling under carbon monoxide leads to diaryl ketones.- Ligandless Pd(OAc)2 also catalyzes the reaction of ArCOCl with NaBAr4 to afford ketones. "... 

Addition of carboxylic acids to alkynes generally requires the presence of strong protic acids or other electrophilic catalysts. It was, however, observed that carboxylic acids having pAa < 4.5 do add to phenylacetylene in the absence of a strong acid catalyst to give enol esters In case of formic acid, addition occurred by simply heating the alkyne in formic acid at 100 C. A variety of diaryl, dialkyl, aralkyl and terminal alkynes react, but dimethyl acetylenedicarboxylate was found to be unreactive. The final product is a ketone, while a stoichiometric amount of carbon monoxide is released. 

There has been a review of palladium-catalysed carbonylative coupling reactions of aryl halides with carbon nucleophiles in the presence of carbon monoxide. It has been shown that rhodium is an efficient catalyst for the homocoupling reaction of arylzinc compounds in the presence of 1 atm of carbon monoxide to give diaryl ketones. Under similar conditions, palladium and nickel catalysts yield biaryls. The beneficial catalysis by rhodium is likely to derive from the ease of migration of the aryl ligand to carbon monoxide in the rhodium(III) intermediate. A rhodium catalyst has also been used in the formation of indole-3-carboxylates by reaction of indoles with alcohols in the presence of carbon monoxide. The catalytic cycle. Scheme 5, is likely to involve metallation of the indole at the 3-position, followed... 

The Pd-catalyzed formation of symmetrical diaryl ketones from arylmercuric salts was first reported by R. F. Heck. The reaction of phenylmercuric chloride with carbon monoxide... 

Arylboronic acids react with carbon monoxide in methanol in the presence of a catalytic amount of Pd(PPh3)4 to give symmetrical diaryl ketones as the major products together with methyl benzoates as the side products (Scheme 28). ... 

Diaryl ketones are important scaffolds in biologically active compoimds, and although several synthetic pathways are available in solution, their application in solid phase synthesis is rare. Yun et aL [85] have developed a high-throughput synthesis of diaryl ketones via a Stille carbonylation on solid phase. Immobilized arylstannanes 39 were subjected to Stille coupling with aryl halides in presence of carbon monoxide (Scheme 23). Not only did the reaction afford products of high yield and purity, but it was also tolerant towards most functional groups. 

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