Catalytic asymmetric synthesis of 19,20-dihydroakuammicine

Abstract

An enantiocontrolled total synthesis of 19,20-dihydroakuammicine using a catalytic asymmetric Michael addition of dimethyl malonate to cyclohexenone as the key step is described. The above catalytic asymmetric Michael addition proceeds quite efficiently in the presence of a heterobimetalic asymmetric catalyst (ALB-KO-t-Bu-MS 4A, 0.3 mol%), giving the corresponding Michael adduct in 94% yield and 99% ee.