Asymmetric Synthesis Catalyzed by Chiral Ferrocenylphosphine-Transition-Metal Complexes. 3. Preparation of Optically Active Allylsilanes by Palladium-Catalyzed Asymmetric Grignard Cross-Coupling

Article abstract of DOI:10.1021/jo00370a006

Asymmetric cross-coupling of the <α-(trimethylsilyl)benzyl>- or <1-(trialkylsilyl)ethyl>-Grignard reagent with alkenyl bromides in the presence of a chiral ferrocenylphosphine-palladium complex, dichloro<(R)-N,N-dimethyl-1-<(S)-2-(diphenylphosphino)ferrocenyl>ethylamine>palladium(II) (PdCl2<(R,S)-PPFA>), as a catalyst, gave optically active allylsilanes which contain an asymmetric carbon atom directly bonded to the silicon atom, e.g., (R)-3-phenyl-3-(trimethylsilyl)propene (3a) (95percent ee), (R,E)-1-phenyl-1-(trimethylsilyl)-2-butene (3b) (85percent ee), (R,Z)-3b (24percent ee), (R,E)-1,3-diphenyl-3- (trimethylsilyl)propene (3c) (95percent ee), (S,E)-1-phenyl-3-(trimethylsilyl)-1-butene (14c) (71percent ee), (S,Z)-14c (59percent ee), (S,E)-1-phenyl-3-(triethylsilyl)-1-butene (16c) (93percent ee), (S,E)-3-(triethylsilyl)-2-pentene (16b) (85percent ee), (S,E,E)-2-(dimethylphenylsilyl)-3,5-heptadiene (15d) (45percent ee), and 1-<1-(trimethylsilyl)ethyl>cyclopentene (21) (37percent ee).The configuration and enantiomeric purity of the allylsilanes were determined with the aid of stereoselective oxidative cleavage of the carbon-silicon bond in optically active alkylsilanes.