Stereoselective synthesis of Δ(1)-pyrroline sulfonamides via a chiral aldehyde mediated cascade reaction

Abstract

Functionalized chiral heterocycles play important roles in drug discovery and development. Cascade reactions are powerful strategies for the construction of structurally complex chiral heterocycles. Herein, a catalytic asymmetric Michael addition/spiroannulation/ring cleavage cascade reaction between NH₂-free glycinate and cyclic 1-azadienes is established by using a novel chiral aldehyde catalyst, which results in the formation of optically active Δ(1)-pyrroline sulfonamides with high efficiency and high diastereo- and enantioselectivities. Notably, the use of the newly developed chiral aldehyde catalyst led to not only an enhanced reaction rate but also reversed chiral induction compared with its analogue bearing the same configurations.