Donor鈥揂cceptor Cyclopropanes as 1,2-Dipoles in GaCl3-Mediated [4 + 2]-Annulation with Alkenes: Easy Access to the Tetralin Skeleton

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• 作者：Roman A. Novikov ; Anna V. Tarasova ; Victor A. Korolev ; Evgeny V. Shulishov ; Vladimir P. Timofeev ; Yury V. Tomilov
• 刊名：Journal of Organic Chemistry
• 出版年：2015
• 出版时间：August 21, 2015
• 年：2015
• 卷：80
• 期：16
• 页码：8225-8235
• 全文大小：485K
• ISSN：1520-6904

文摘

A new process for (4 + 2)-annulation of donor鈥揳cceptor cyclopropanes (DACs) with unsaturated compounds in the presence of anhydrous GaCl₃ has been developed. In this process, DACs act as sources of formal 1,2- and 1,4-dipoles to give polysubstituted tetralins in high yields and with high regio- and diastereoselectivity. Alkenes with both aryl and alkyl substituents at the double bond undergo this reaction equally readily. A most likely mechanism of the reaction has been proposed. It involves preliminary generation of a key 1,2-dipolar gallium complex and its subsequent participation in annulation with an alkene.