Diastereo- and Enantioselective Synthesis of Nitroso Diels-Alder-Type Bicycloketones Using Dienamine: Mechanistic Insight into Sequential Nitroso Aldol/Michael Reaction and Application for Optically P

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• 作者：Norie Momiyama ; Yuhei Yamamoto ; Hisashi Yamamoto
• 刊名：Journal of the American Chemical Society
• 出版年：2007
• 出版时间：February 7, 2007
• 年：2007
• 卷：129
• 期：5
• 页码：1190 - 1195
• 全文大小：333K
• 年卷期：v.129,no.5(February 7, 2007)
• ISSN：1520-5126

文摘

This article presents complete diastereo- and highly enantioselective synthesis of nitroso Diels-Alder-type bicycloketones using dienamine. With the hydrogen bonding of two hydroxyls in the bulkybinaphthol 1c, high enantioselectivities and complete diastereoselectivity are realized in 2-oxa-3-aza-bicycloketone synthesis. On the other hand, ,-unsaturated ketone can be employed as diene precursor,utilizing readily available tetrazole catalyst 3b, to provide the 3-oxa-2-aza-bicycloketones in moderate yieldswith complete enantioselectivities. Investigation into the reaction utilizing 2-morpholino-4,4-diphenylcyclohexadiene 2d clearly indicated that cyclization with the bulky binaphthol 1c is involved in the sequentialprocess, the N-nitroso aldol reaction, followed by Michael addition. In addition, optically pure 1-amino-3,4-diol is synthesized from 2-oxa-3-aza-bicycloketones. Use of p-phenoxynitrosobenzene allows access toprotected amino diol via cleavage of the N-Ph bond.