Concise synthesis of functionalized benzocyclobutenones

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• 作者：P.-H. Chen^&dagger ; ; Nikolas A. Savage^&dagger ; ; Guangbin Dong ; ^{gbdong@cm.utexas.edu" class="auth_mail}
• 关键词：Benzocyclobutenone ; Cycloaddition ; Benzyne ; Dehydrohalogenation ; Benzocyclobutenol
• 刊名：Tetrahedron
• 出版年：8 July 2014
• 年：2014
• 卷：70
• 期：27-28
• 页码：4135-4146
• 全文大小：2205 K

文摘

A concise approach to access functionalized benzocyclobutenones from 3-halophenol derivatives is described. This modified synthesis employs a [2+2] cycloaddition between benzynes generated from dehydrohalogenation of aryl halides using LiTMP and acetaldehyde enolate generated from n-BuLi and THF, followed by oxidation of the benzocyclobutenol intermediates to provide benzocyclobutenones. The [2+2] reaction can be run on a 10-g scale with an increased yield. A number of functional groups including alkenes and alkynes are tolerated. Coupling of benzynes with ketene silyl acetals to give 8-substituted benzocyclobutenones is also demonstrated.