Threonine-derived thioureas as bifunctional organocatalysts for enantioselective Michael addition

Abstract

A series of threonine-derived thioureas were developed through the facile modification of l-threonine chiral scaffold. The enantioselective efficiency were evaluated in the catalytic asymmetric Michael addition of 2-hydroxy-1,4-naphthoquinone to nitroalkenes, which afforded the chiral nitroalkylated naphthoquinone derivatives in high yields (up to 93%) and enantio-selectivities (up to 99% ee) under low catalyst loading (3 mol%).