Synthesis of some new tertiary amines and their application as co-catalysts in combination with l-proline in enantioselective Baylis–Hillman reaction between o-nitrobenzaldehyde and methyl vinyl ketone

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• 作者：Hongying Tang ; Guofeng Zhao ; Zhenghong Zhou ; Qilin Zhou and Chuchi Tang
• 刊名：Tetrahedron Letters
• 出版年：2006
• 出版时间：7 August 2006
• 年：2006
• 卷：47
• 期：32
• 页码：5717-5721
• 全文大小：113 K

文摘

A chiral benzodiazepine derivative 1 was synthesized starting from o-nitrobenzoyl chloride and methyl l-prolinate hydrochloride. Diastereomeric (1R,2R,1′S)-(+)-2-[N-methyl-N-(α-phenylethyl)amino]cyclohexanol 3a and (1S,2S,1′S)-(+)-2-[N-methyl-N-(α-phenylethyl)amino]cyclohexanol 3b were synthesized starting from (S)-α-phenylethylamine and cyclohexene oxide via ring-opening, diastereomer separation and N-methylation. (S,S)-octahydrodipyrrolo[1,2-a:1′,2′-d]pyrazin 5 was synthesized from methyl l-prolinate. Chiral tertiary amines 1, 3a, 3b and 5 almost cannot catalyze the Baylis–Hillman reaction between o-nitrobenzaldehyde and methyl vinyl ketone (MVK). However, they functioned as efficient catalysts for this reaction in the presence of l-proline. The corresponding adducts were obtained in good yields with enantioselectivity of 83 % ee, 81 % ee, 51 % ee and 66 % ee, respectively.