p-Toluenesulfonic acid-mediated cyclization of o-(1-alkynyl)anisoles or thioanisoles: synthesis of 2-arylsubstituted benzofurans and benzothiophenes
作者:Maud Jacubert、Abdallah Hamze、Olivier Provot、Jean-François Peyrat、Jean-Daniel Brion、Mouad Alami
DOI:10.1016/j.tetlet.2009.03.087
日期:2009.7
A variety of 2-arylbenzo[b]furans are readily prepared in good to excellent yields from the cyclization of o-(1-alkynyl)anisole derivatives under mild reaction conditions using an alcoholic media, p-toluenesulfonic acid under microwave irradiation. Starting from the corresponding o-(1-alkynyl)thioanisole derivatives, this friendly and environmentally free-metal procedure has been successfully extended to the synthesis of benzo[b]thiophenes. Relative to the electronic nature of the substituents, the selectivity of the cyclization reaction from differently o,o'-substituted diarylalkynes is also discussed. (C) 2009 Published by Elsevier Ltd.