Catalytic dehydrative peptide synthesis with gem-diboronic acids

Article abstract of DOI:10.1021/acscatal.9b03894

Alkane-gem-diboronic acids have emerged as versatile organoboron catalysts for dehydrative amidation of α-Amino acids. A phenol-substituted multiboron catalyst with a B-C-B structure outperformed simple arylboronic acids in the condensation of α-Amino acids with suppressed epimerization of electrophiles. gem-diboronic acid catalysis were compatible with various O, N, and S-functionalized α-Amino acids bearing N-protecting groups including common carbamates used in peptide synthesis (Boc, Cbz, Fmoc). N-Trifluoroacetyl protection enabled an unprecedented catalytic dehydrative peptide synthesis at room temperature. Preliminary mechanistic studies revealed carboxylate-binding nature of gem-diboronic acids, orthogonal to the activation of carboxylic acids by arylboronic acids. The distinctive reactivity of the gem-diboronic acids would open prospects for mild catalytic peptide condensation.