Highly Efficient Synthesis of Heterocyclic and Alicyclic β2‐Amino Acid Derivatives by Catalytic Asymmetric Hydrogenation |
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Authors: | Lanning Li Bin Chen Yuanyuan Ke Qing Li Yue Zhuang Kun Duan Yichun Huang Dr Jiyan Pang Prof?Dr Liqin Qiu |
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Institution: | 1. School of Chemistry and Chemical Engineering, Guangdong Engineering Research Center of Chiral Drugs, Sun Yat‐sen University, No. 135 Xingangxi Road, Guangzhou 510275 (People's Republic of China), Fax: (+86)?20‐8411‐0996;2. Huizhou Research Institute of Sun Yat‐sen University, Sun Yat‐sen University, Dayawan, Huizhou (People's Republic of China) |
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Abstract: | A valuable class of new heterocyclic and alicyclic prochiral α‐aminomethylacrylates has been conveniently synthesized through a three‐step transformation involving a Baylis–Hillman reaction, O‐acetylation, and a subsequent allylic amination. The corresponding novel β2‐amino acid derivatives were prepared with excellent enantioselectivities and high yields by catalytic asymmetric hydrogenation using the catalyst rhodium(Et‐Duphos) (Et‐Duphos=2′,5′,2′′,5′′‐tetraethyl‐1,2‐bis(phospholanyl)benzene)) under mild reaction conditions (up to 99 % ee and S/C=1000). The influence of the substrate on the enantioselectivity and reactivity is investigated, and the most suitable substrate configuration for the highly efficient enantioselective hydrogenation of β‐substituted α‐aminomethylacrylates under the Rh–Duphos system is reported. The current protocol provides a very practical, facile, and scalable method for the preparation of heterocyclic and alicyclic β2‐amino acids and their derivatives. |
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Keywords: | amino acids asymmetric catalysis heterocycles hydrogenation rhodium |
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