But-2-ynylbisoxycarbonyl chloride: a novel C2-symmetric reagent for the protection of amines and amino acids

reaction: see text] A novel C2-symmetric protecting group for amines, the but-2-ynylbisoxycarbonyl (Bbc) group, is developed, which can be deblocked with tetrathiomolybdate under neutral conditions. One equivalent of the bischloroformate, BbcCl, is used for the protection of 2 equiv of the amine. Its application in peptide synthesis is established through the synthesis of a tripeptide, and its orthogonality with Cbz, Fmoc, and Boc groups has been studied.