Highly Stereoselective N‐Terminal Functionalization of Small Peptides by Chiral Phase‐Transfer Catalysis

Virtually complete chirality transfer has been realized in the N-terminal alkylation of small, Schiff-base activated peptides under mild phase-transfer conditions, in which finely tuned chiral quaternary ammonium salts are used as catalysts. Repeated extension and alkylation of the N-terminal position can lead selectively to nonnatural oligopeptides (see picture).