Wittig Reaction: Domino Olefination and Stereoselectivity DFT Study. Synthesis of the Miharamycins鈥?Bicyclic Sugar Moiety

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• 作者：Vasco Cachatra ; Andreia Almeida ; Jo茫o Sardinha ; Susana D. Lucas ; Ana Gomes ; Pedro D. Vaz ; M. Helena Flor锚ncio ; Rafael Nunes ; Diogo Vila-Vi莽osa ; Maria Jos茅 Calhorda ; Am茅lia P. Rauter
• 刊名：Organic Letters
• 出版年：2015
• 出版时间：November 20, 2015
• 年：2015
• 卷：17
• 期：22
• 页码：5622-5625
• 全文大小：346K
• ISSN：1523-7052

文摘

2-O-Acyl protected-d-ribo-3-uloses reacted with [(ethoxycarbonyl)methylene]triphenylphosphorane in acetonitrile to afford regio- and stereoselectively 2-(Z)-alkenes in 10鈥?0 min under microwave irradiation. This domino reaction is proposed to proceed via tautomerization of 3-ulose to enol, acyl migration, tautomerization to the 3-O-acyl-2-ulose, and Wittig reaction. Alternatively, in chloroform, regioselective 3-olefination of 2-O-pivaloyl-3-uloses gave (E)-alkenes, key precursors for the miharamycins鈥?bicyclic sugar moiety.