Dual Catalysis Using Boronic Acid and Chiral Amine: Acyclic Quaternary Carbons via Enantioselective Alkylation of Branched Aldehydes with Allylic Alcohols

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• 作者：Xiaobin Mo ; Dennis G. Hall
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：August 31, 2016
• 年：2016
• 卷：138
• 期：34
• 页码：10762-10765
• 全文大小：402K
• 年卷期：0
• ISSN：1520-5126

文摘

A ferrocenium boronic acid salt activates allylic alcohols to generate transient carbocations that react with in situ-generated chiral enamines from branched aldehydes. The optimized conditions afford the desired acyclic products embedding a methyl-aryl quaternary carbon center with up to 90% yield and 97:3 enantiomeric ratio, with only water as the byproduct. This noble-metal-free method complements alternative methods that are incompatible with carbon–halogen bonds and other sensitive functional groups.