Catalytic Asymmetric Aza-Morita−Baylis−Hillman Reaction of Methyl Acrylate: Role of a Bifunctional La(O-iPr)3/Linked-BINOL Complex

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• 作者：Takafumi Yukawa ; Bianca Seelig ; Yingjie Xu ; Hiroyuki Morimoto ; Shigeki Matsunaga ; Albrecht Berkessel ; Masakatsu Shibasaki
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：September 1, 2010
• 年：2010
• 卷：132
• 期：34
• 页码：11988-11992
• 全文大小：319K
• 年卷期：v.132,no.34(September 1, 2010)
• ISSN：1520-5126

文摘

The catalytic asymmetric aza-Morita−Baylis−Hillman reaction using unactivated methyl acrylate is described. A simple Lewis acidic metal catalyst, such as La(OTf)₃, was not suitable for the reaction, but rare earth metal alkoxide/linked-BINOL complexes possessing bifunctional Lewis acid and Brønsted base properties efficiently promoted the reaction in combination with an achiral nucleophilic organocatalyst. The combined use of a La(O-iPr)₃/(S,S)-TMS-linked-BINOL complex with a catalytic amount of DABCO promoted the aza-Morita−Baylis−Hillman reaction of a broad range of N-diphenylphosphinoyl imines. Products from aryl, heteroaryl, and alkenyl imines were obtained in 67−99% yield and 81−95% ee. It is noteworthy that isomerizable alkyl imines could be employed as well, giving products in 78−89% yield and 94−98% ee. Initial rate kinetic studies as well as kinetic isotope effect experiments using α-deuterio-methyl acrylate support the importance of both the nucleophilicity of La-enolate and the Brønsted basicity of a La-catalyst for promoting the reaction.