A new synthesis of phthalides by internal trapping in ortho-lithiated carbamates derived from benzylic alcohols

…, C Lamas, L Castedo, D Dominguez

Index: Paleo, M. Rita; Lamas, Carlos; Castedo, Luis; Dominguez, Domingo Journal of Organic Chemistry, 1992 , vol. 57, # 7 p. 2029 - 2033

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Citation Number: 27

Abstract

The addition of t-BuLi to a low-temperature THF solution of o-bromocarbamates 2 leads to ortho-lithiated intermediates 3, in which internal trapping by the electrophile on the side chain then takes place. This novel Parham-type anionic cyclization procedure affords the variously substituted phthalides 5 in high yields and can also be used for the preparation of lactones 8, which are useful for the synthesis of aristocularine alkaloids.