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 α,β-unsaturated aldehydes resulted in high yields and remarkable enantioselectivities. Addition of γ-substituted allylstannanes such as 2-butenyltributylstannane and trialkyl-2,4-pentadienylstannanes exclusively gave γ-adducts. High anti-selectivity was also obtained in the reaction with 2-butenyltributylstannane, irrespective of the configuration at the double bond.