Novel Pd^II-Mediated Cascade Carboxylative Annulation to Construct Benzo[<i>b</i>]furan-3-carboxylic Acids

Abstract

[reaction: see text] Benzo[b]furan-3-carboxylic acid (2) was generated from 1 by forming three new bonds in one step via a Pd(II)-mediated cascade carboxylative annulation. The proposed mechanism was supported by the observation of an unusual acetylation of 1 as a side reaction together with an (18)O-labeling study.