89300-28-7Relevant articles and documents
Palladium-promoted double-carbonylation reactions. Reactions of organopalladium compounds with carbon monoxide and amines to give α-keto amides
Ozawa, Fumiyuki,Sugimoto, Takeshi,Yuasa, Yasuhiro,Santra, Manoranjan,Yamamoto, Takakazu,Yamamoto, Akio
, p. 683 - 692 (2008/10/08)
A variety of mono- and diorganopalladium complexes, trans-PdR(X)L2 (R = Me, Et, and Ph; X = Cl, Br, I, and aryloxo; L = teritary phosphine ligand) and cis-PdMe2L2, react with carbon monoxide and secondary amines under mild conditions to give α-keto amides as double-carbonylation products. A series of acylpalladium complexes, trans-Pd(COR)X(PMePh2)2 (R = Ph, X = Cl, Br, and I; R = Me, X = Cl), the presumed reaction intermediates, were prepared, and their reactions with carbon monoxide and amines were investigated. The reaction of benzoylpalladium having bromo and iodo ligands with CO and amines proceeds more smoothly in a solvent of higher polarity than in nonpolar solvents, whereas the reaction with benzoyl(chloro)palladium complex takes place more readily in nonpolar solvents. On the basis of the effect of the solvent polarity on the reactions, two types of reaction pathways have been proposed: one involves an ionic acyl(carbonyl)palladium intermediate [PhCOPd(CO)L2]+X- attacked by amine to give acyl-carbamoyl species, from which α-keto amide is reductively eliminated, while the other mechanism proceeds through a neutral acyl-carbonyl intermediate [Pd(COR)(CO)XL]. Evidence to support the former mechanism has been obtained from the experiments using trans-[Pd(COPh)(CO)(PMePh2)2]ClO4, which is prepared by the treatment of trans-Pd(COPh)Cl(PMePh2)2 with AgClO4 and CO.
