Radical induced fragmentation in a benzoxocane ring system: application to the synthesis of elvirol and a formal synthesis of 7,8-dihydroxycalamenene

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• 作者：Amalesh Roy ; Kazi Tuhina ; Bidyut Biswas ; Ramanathapuram V. Venkateswaran
• 关键词：Barton deoxygenation ; Radical induced fragmentation ; Elvirol ; 7 ; 8-Dihydroxycalamenene
• 刊名：Tetrahedron
• 出版年：2012
• 出版时间：12 August, 2012
• 年：2012
• 卷：68
• 期：32
• 页码：6575-6580
• 全文大小：396 K

文摘

A novel radical induced fragmentation in a benzoxocane ring system has been employed for a synthesis of elvirol 8 and an advanced intermediate in the synthesis of 7,8-dihydroxycalamenene 20. The coumarins 9, 22 were taken through a sequence of reactions to the benzoxocanols 16, 30, which when subjected to Barton¡¯s deoxygenation conditions involving conversion to the corresponding thionocarbonates 17, 31 followed by exposure to tri-n-butyltin hydride, underwent a radical induced fragmentation to furnish elvirol 8 and the curcuphenol derivative 32, which was converted to the dimethoxy compound 33. This had served as an advanced intermediate in a previous synthesis of dihydroxycalamenene.