Preparation of cis-and trans-2, 3-Dimethyl-2, 3-dihydrobenzofurans and Related Compounds. Cyclizations Involving Oxonium Ions1

DP Brust, DS Tarbell, SM Hecht…

Index: Brust,D.P. et al. Journal of Organic Chemistry, 1966 , vol. 31, p. 2192 - 2201

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Citation Number: 16

Abstract

cyclization in sulfuric acid was investigated. 0-Allylphenols have long been known to be cyclized by acids to dihydrobenzofurans or chr~ mans.~~~~' Cyclization of B-2 occurred readily in 98% sulfuric acid at room temperature to give a good yield of the diastereoisomeric dihydrobenzofurans, trans-and cis-5, 7-dichloro-2, 3-dihydro-2, 3, 4- trimethylbenzofuran (I and J)(Scheme