LETTER	Synlett 2007: 1026-1030   DOI: 10.1055/s-2007-973890
© Georg Thieme Verlag Stuttgart · New York
An Efficient Synthesis of Amides and Esters via Triacyloxyboranes
Zhongping Huang*, John E. Reilly, Ronald N. Buckle
Department of Medicinal Chemistry, Albany Molecular Research Inc., Albany, NY 12212, USA Fax: +1(518)4640289; e-Mail: zhongping.huang@albmolecular.com ;
Received 6 November 2006

Abstract

Borane-tetrahydrofuran complex or borane-methyl ­sulfide complex is used to activate carboxylic acids to generate triacyloxyboranes. The triacyloxyboranes can be effectively reacted with various nucleophiles including alkylamines, arylamines, hydrazides, alcohols and phenols at reflux in toluene to provide the corresponding amides and esters in excellent yield. Aliphatic carboxylic acids are selectively esterified in the presence of aromatic carboxylic acids under the borane conditions.

Key words

triacyloxyboranes - amides - esters - borane-tetrahydrofuran complex - borane-methyl sulfide complex - selectivity