Chiral cinchona alkaloid-derived thiourea catalyst for enantioselective synthesis of novel β-amino esters by Mannich reaction

摘要

A cinchona alkaloid-derived thiourea catalyst has been designed to access new asymmetric β-amino esters bearing benzothiazole moiety by utilizing a Mannich reaction between an imine and a malonate. A simultaneous activation of the two imine functionalities and malonate by the bifunctional chiral organocatalyst is proposed to account for the good yields (71-91%) and high enantiomeric excess (89.4-98.5%) under mild conditions.