Synthesis of functionalized benzoxaboroles

Abstract

2-Formylphenylboronic acids upon reaction with activated olefins such as acrylates, methyl vinyl ketone, and acrylonitrile, etc. via Baylis-Hillman reaction to provide functionalized benzoxaboroles. The corresponding homologated benzoxaboroles were synthesized via Barbier allylation reaction of 2-formylphenylboronic acids with α-bromomethylacrylates. Several novel benzoxaborole derivatives were synthesized starting from 2-formylphenylboronic acid utilizing Passerini reaction and aldol reaction protocols as the key step. An efficient methodology for the preparation of α-hydroxyamides via boric acid mediated addition of isonitriles on to aldehydes has been developed. The reaction of isonitriles with α-boronobenzaldehyde takes place under intramolecular catalysis conditions to provide functionalized benzoxaboroles.