A simple and efficient method for the syntheses of thioether cyclic peptides

Abstract A general method is described for the synthesis of thioether cyclic peptides. The thioether linkage of cyclic peptides was formed in moderate to high yield through an intramolecular substitution of the chloro group of β-chloroalanine with the thiol group of cysteine. The peptides containing β-chloroanaline were readily prepared on resin by converting a TBDMS-protected hydroxyl group of homoserine to a chloro group with triphenylphosphine dichloride.