Borinic acid catalysed peptide synthesisElectronic supplementary information (ESI) available. See DOI: 10.1039/c5cc06177f

The catalytic synthesis of peptides is a major challenge in the modern organic chemistry hindered by the well-established use of stoichiometric coupling reagents. Herein, we describe for the first time that borinic acid is able to catalyse this reaction under mild conditions with an improved activity compared to our recently developed thiophene-based boronic acid. This catalyst is particularly efficient for peptide bond synthesis affording dipeptides in good yields without detectable racemization. 2-Chlorophenylborinic acid is reported to catalyze dipeptide synthesis in the presence of molecular sieves with no racemization.