N-Heterocyclic Carbene-Promoted Annulation Reaction of Allenals with Chalcones: Synthesis of Polysubstituted Pyranyl Aldehydes

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• 作者：Dengke Ma ; Youai Qiu ; Jianxin Dai ; Chunling Fu ; Shengming Ma
• 刊名：Organic Letters
• 出版年：2014
• 出版时间：September 19, 2014
• 年：2014
• 卷：16
• 期：18
• 页码：4742-4745
• 全文大小：384K
• ISSN：1523-7052

文摘

A general N-heterocyclic carbene (NHC)-promoted annulation reaction of allenals with chalcones affording polysubstituted pyranyl aldehydes has been developed. Three mechanistic possible pathways have been proposed. The NHC attacks the center carbon of allenals or acts as a base for deprotonation and then undergoes a 1,4-addition with chalcones, followed by sequential reactions giving the final products.