Palladium‐Catalyzed Suzuki Coupling with Terminal Alkynes — Application to the Synthesis of 2,3‐Disubstituted Benzo[b]furans.

Abstract

the Synthesis of 2,3-Disubstituted Benzo[b]furans. -Suzuki coupling of acetylenic boronic esters, generated in situ, with ortho-halogeno methoxy-or silyloxybenzenes is followed by deprotection/5-endo-dig-iodocyclization. 2-Substituted-3-iodobenzofurans (III) are thus obtained either in a one-pot reaction or via isolated coupling products. The latter, i.e. (IX) or (XII) are transformed into the target compounds by various deprotection/intramolecular cyclization reactions. -(COLOBERT*, F.; CASTANET, A.-S.; ABILLARD, O.; Eur. J. Org. Chem. 2005, 15, 3334-3341; Lab. Stereochim., CNRS, Univ. Louis Pasteur, F-67087 Strasbourg, Fr.; Eng.) -Klein 48-126