Enhanced cooperative activation effect in the hydrolytic kinetic resolution of epoxides on [Co(salen)] catalysts confined in nanocages.

The solid catalyst with high catalytic activity and enantioselectivity in the hydrolytic kinetic resolution (HKR) of epoxides was prepared by confining Co(Salen) in the nanocage of SBA-16 through reducing the pore entrance size using a silylation method. It was found that the activity of the solid catalysts increased with the number of [Co(Salen)] molecules per nanocage increasing, and the solid catalyst with more than two chiral [Co(Salen)] molecules in one nanocage of SBA-16 exhibits much higher activity and enantioselectivity than the homogeneous [Co(Salen)] catalyst in the HKR of epoxides at low substrate/catalyst ratio. The significantly improved activity of the solid catalyst is due to a high local concentration of [Co(Salen)] in nanospace because of the enhanced cooperative activation effect of [Co(Salen)] molecules.