Cascade C–H Annulation of Aldoximes with Alkynes Using O2 as the Sole Oxidant: One-Pot Access to Multisubstituted Protoberberine Skeletons

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• 作者：Junbin Tang ; Shiqing Li ; Zheng Liu ; Yinsong Zhao ; Zhijie She ; Vilas D. Kadam ; Ge GaoJingbo Lan ; Jingsong You
• 刊名：Organic Letters
• 出版年：2017
• 出版时间：February 3, 2017
• 年：2017
• 卷：19
• 期：3
• 页码：604-607
• 全文大小：416K
• ISSN：1523-7052

文摘

A cascade double C–H annulation of aldoximes with alkynes to produce benz[a]acridizinium salts is developed by using a simple catalytic system of [Cp*Rh(OAc)₂]₂ in the presence of Zn(OTf)₂ with oxygen as the sole oxidant. In addition, the challenging C–H annulation of aldoximes with alkynes, especially arylalkynes, to synthesize 1H-isoquinolines is also achieved under slightly modified conditions. This protocol provides an efficient one-pot access to multisubstituted dehydroberberinium skeletons from simple starting materials, which can be easily transformed into berberinium and tetrahydroberberine skeletons by controlled hydrogenation.