Chiral Bisphosphine BINAP-Stabilized Gold and Palladium Nanoparticles with Small Size and Their Palladium Nanoparticle-Catalyzed Asymmetric Reaction

Abstract

The reduction of tetrachloroaurate or potassium tetrachloropalladate with sodium borohydride in the presence of optically active 2,2‘-bis(diphenylphosphino)-1,1‘-binaphthyl [BINAP] gave the chiral (S)- or (R)-BINAP-stabilized gold or palladium nanoparticles which showed the small core (1.7 nm for BINAP−Au and 2.0 nm for BINAP−Pd) with narrow size distribution and remarkably high stability. Asymmetric hydrosilylation of styrene with trichlorosilane in the presence of chiral BINAP−Pd nanoparticles afforded an optically active 1-phenyl-1-trichlorosilylethane which was converted into an optically active 1-phenylethanol (95% enantiomeric excess) by oxidative cleavage of the carbon−silicon bond.