Type III intramolecular [2+ 2] cycloadditions of vinylketenes

BB Snider, AJ Allentoff, YS Kulkarni

Index: Snider, Barry B.; Allentoff, Alban J.; Kulkarni, Yashwant S. Journal of Organic Chemistry, 1988 , vol. 53, # 22 p. 5320 - 5328

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Citation Number: 12

Abstract

Treatment of trans a,@-unsaturated acid chlorides with Et, N in benzene at reflux gives a ca. 1: l mixture of cis and trans a,@-unsaturated ketenes in excellent yield. If there is a second double bond in the side chain, the cis isomer undergoes a type I11 intramolecular cycloaddition to produce a bicyclo [3.2. 0] hept-3-en-6-one and/or a bicyclo [3. ll] hept-2-en-6- one in 3040% yield from the acid chloride. The effect of substituents on the ...