Asymmetric addition of allylic stannanes to aldehydes catalyzed by BINAP•Ag(I) complex

Catalytic asymmetric allylation of aldehydes with allylic trialkylstannanes was achieved with BINAP . AgOTf complex as catalyst. The chiral silver(I) catalyst was readily prepared by stirring an equimolar mixture of BINAP and silver(I) triflate in THF at room temperature. The allylation of a variety of aromatic and alpha,beta -unsaturated aldehydes resulted in high yields and remarkable enantioselectivities. Addition of gamma -substituted allylstannanes such as 2-butenyltributylstannane and trialkyl-2,4-pentadienylstannanes exclusively gave gamma -adducts. High anti-selectivity was also obtained in the reaction with 2-butenyltributylstannane, irrespective of the configuration at the double bond.