Synthesis of Benzoxazoles via an Amine-Catalyzed [4 + 1] Annulation

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• 作者：Aiguo Song ; Xiaobei Chen ; Xixi Song ; Xinshuai Zhang ; Shilei Zhang ; Wei Wang
• 刊名：Organic Letters
• 出版年：2013
• 出版时间：May 17, 2013
• 年：2013
• 卷：15
• 期：10
• 页码：2510-2513
• 全文大小：250K
• 年卷期：v.15,no.10(May 17, 2013)
• ISSN：1523-7052

文摘

An unprecedented simple pyrrolidine catalyzed [4 + 1] annulation reaction of ynals with N-protected-2-aminophenols is reported. The utilization of the unique property and reactivity of the C鈮 triple bond in ynals leads to two consecutive conjugate addition reactions at the same 尾-position with pyrrolidine via iminium activation. The powerful cascade process affords a new alternative approach to biologically and synthetically important benzoxazoles in high yields (83鈥?5%).