Boric acid catalyzed bromination of a variety of organic substrates: an eco-friendly and practical protocol

Abstract

An environmentally benign, easy to operate, and practical protocol for the regioselective bromination of aromatic compounds using boric acid as a recyclable catalyst, KBr as the source of bromide and hydrogen peroxide as the oxidant is described. Peroxoborate generated in solution, from the reaction of boric acid and H2O2, very effectively catalyses the bromination of organic substrates at room temperature in a selective manner. The catalyst used is inexpensive, eco-friendly, safe to handle, and recyclable. The methodology is chemoselective for dibenzylidineacetone and regioselective for the other substrates. High yields of the products, mild reaction conditions, high selectivity, use of H2O or C2H5OH as solvent, and redundancy of bromine are some of the major advantages of the synthetic protocol.