Catalytic Asymmetric Decarboxylative Mannich Reaction of Malonic Acid Half Esters with Cyclic Aldimines: Access to Chiral β-Amino Esters and Chroman-4-amines

An enantioselective decarboxylative Mannich reaction of malonic acid half esters (MAHEs) with cyclic aldimines has been accomplished by employing the copper(I)/(R,R)-Ph-Box complex as chiral catalyst. The desired β-amino esters were obtained in good to high yields with excellent enantioselectivities. Furthermore, one of the corresponding Mannich products could be readily transformed into chiral chroman-4-amines without loss of enantioselectivity, which is a key intermediate of the human Bradykinin B1 receptor antagonist.