A novel and efficient methodology for thio-Michael addition in the synthesis of cis-β-thio-α-aminoacid derivatives using Zn[(L)-Pro]2 as heterogeneous catalyst

A simple, efficient and green chemical ultrasound assisted thio-Michael addition reaction between thiols and (Z)-azlactones aiming to produce non-natural amino acid derivatives by using chiral Zn[(L)-Pro]2 as a heterogeneous catalyst is herein described. The product was obtained in good to excellent yields presenting high diastereoselectivity.