Diastereoselective reductive Mannich-type coupling of acrylates and aldimines with Rh(Phebox) catalyst

The conjugate reduction of α,β-unsaturated esters such as acrylates, crotonate, and cinnamates followed by Mannich-type coupling toward aldimines was efficiently promoted by rhodium-bis(oxazolinyl)phenyl catalyst and alkoxyhydrosilanes to show high anti-selectivity up to 99.

The coupling reaction with α,β-unsaturated esters and aldimines catalyzed by Rh(Phebox) complex was realized to give β-aminoesters in good to excellent yields with high diastereoselectivity up to 99%.