A New Catalytic Activity of Antimony(III) Chloride in Palladium(0)-Catalyzed Conjugate Addition of Aromatics to .alpha.,.beta.-Unsaturated Ketones and Aldehydes with Sodium Tetraphenylborate and Arylboronic Acids
作者:Chan Sik Cho、Shin-ichi Motofusa、Kouichi Ohe、Sakae Uemura、Sang Chul Shim
DOI:10.1021/jo00109a019
日期:1995.2
A remarkable catalytic effect of antimony(III) chloride is disclosed in palladium(0)-catalyzed conjugate addition of aromatics to alpha,beta-unsaturated ketones and aldehydes with sodium tetraphenylborate and arylboronic acids in acetic acid at 25 degrees C. Several other metal chlorides such as AlCl3, SnCl4, AsCl3, TiCl4, FeCl3, MoCl5, and CeCl3 are also effective in some cases, but SbCl3 is the salt of choice. Two key steps are proposed for this reaction: one is the oxidative addition of a C-B bond to Pd(0) forming an arylpalladium species, and the other is the formation of an antimony enolate derived from the initial coordination of SbCl3 to the carbonyl oxygen of an organopalladium intermediate.