Controlled Synthesis of 2- and 3-Substituted Benzo[b]furans
Tao Pei*, Cheng-yi Chen, Lisa DiMichele and Ian W. Davies
*Department of Process Chemistry, Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, United States, Email: tao_peimerck.com
T. Pei, C.-y. Chen, L. DiMichele, I. W. Davies, Org. Lett., 2010, 12, 4972-4975.
DOI: 10.1021/ol102123u (free Supporting Information)
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Addition of a range of Grignard reagents to 1-(2-hydroxyphenyl)-2-chloroethanones generates alkoxide intermediates, which can form either 2-substituted benzo[b]furans via a [1,2]-aryl migration or 3-substituted benzo[b]furans via a direct cyclization and dehydration sequence. A temperature-dependent [1,2]-aryl migration mechanism for the formation of 2-substituted benzo[b]furan is proposed.
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