Catalytic asymmetric hydrosilylation of olefins: I. Chiral phosphine-platinum(II) complexes as hydrosilylation catalysts

Abstract

Several platinum(II) complexes containing chiral phosphines, ( R)-benzyl-methylphenylphosphine (BMPP). ( R)-methylphenyl- n-propylphosphine (MPPP), and menthyldiphenylphosphine (MDPP), were prepared. Catalytic asymmetric hydrosilylation has been achieved for the first time in the reaction of methyldichlorosilane with 1,1-disubstituted prochiral olefins, α-methyl-styrene, 2,3-dimethyl-1-butene, and 2-methyl-1-butene, using a platinum catalyst precursor [L★PtCl 2] 2 (L★ = BMPP and MPPP), and partly optically active adducts of the type RMeCHCH 2SiMeCl 2 (R = Ph, i-Pr, and Et) have been obtained. With trichlorosilane, the asymmetric addition reaction was always accompanied by isomerization or dimerization of the olefins. The chiral platinum complex-catalyzed addition-cyclization of 4-pentenyldimethylsilane also gave rise to an optically active 2-methyl-1-silacyclopentane derivative.