Enantioselective Nitro‐Michael Addition Catalyzed by N‐Terminal Guanidinylated Helical Peptide

Abstract

AbstractEnantioselective Michael addition of β‐dicarbonyl compounds toward nitroalkenes were realized by using an immobilized, N‐terminal‐guanidinylated peptide, H2N−C(=NH)−Trp−Trp−(Leu−Leu−Aib)3−PEG−PS‐resin (Aib=2‐aminoisobutyric acid), as catalyst. Viable nucleophiles were acetylacetone, dimethyl malonate, and β‐ketoesters. The electrophiles include the β‐nitrostryrenes with various substituents on the benzene ring and the aliphatic nitroalkenes. Sterically congested α‐ethoxycarbonyl‐β‐nitrostryrene also successfully reacted. The resin‐supported catalyst could be recycled for five times.magnified image