Cobalt-Catalyzed N-Alkylation of Amines with Alcohols

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• 作者：Guoqi Zhang ; Zhiwei Yin ; Shengping Zheng
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：January 15, 2016
• 年：2016
• 卷：18
• 期：2
• 页码：300-303
• 全文大小：279K
• ISSN：1523-7052

文摘

A well-defined nonprecious metal cobalt(II) catalyst based on a pincer PNP ligand has been employed for the efficient N-alkylation of both aromatic and aliphatic amines with alcohols. A subtle change of reaction conditions (simply adding 4 ? molecular sieves) was observed to readily switch the resulting products (amines vs imines) with high chemoselectivity. A range of alcohols and amines including both aromatic and aliphatic substrates were efficiently converted to secondary amines in good-to-excellent yields when 2 mol % cobalt catalyst was used. Additional experiments indicate that a hydrogen-borrowing mechanism is responsible for the tandem acceptorless dehydrogenation/condensation/hydrogenation process.