Design, Synthesis, and Application of Multiboron Heterocycle to Direct Amidation Catalyst

Abstract

The synthesis of a multiboron heterocycle and its application to a direct amidation catalyst are described. The heterocycle comprised of B₃NO₂ is called DATB. The DATB-catalyzed direct amide formation is well suited for the synthesis of a wide range of amides, including previously intractable ones. The catalysis can also be applied to peptide synthesis and N-acylation of sulfoximines. The most active DATB contains four boron atoms in its structure, and the detailed mechanistic study revealed their distinctive roles in the catalytic cycle, depending on the given chemical environment. A pyrimidine containing analog was also developed and evaluated as a more readily accessible amidation catalyst than the original one. The Pym-DATB is now available from a commercial vendor. Current trends and future perspective in the boron-catalyzed direct amidation are also discussed.