Direct Asymmetric Synthesis of β-Bis-Aryl-α-Amino Acid Esters via Enantioselective Copper-Catalyzed Addition of p-Quinone Methides

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• 作者：Fu-Sheng He ; Jing-Hai Jin ; Zhong-Tao Yang ; Xingxin Yu ; John S. Fossey ; Wei-Ping Deng
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：February 5, 2016
• 年：2016
• 卷：6
• 期：2
• 页码：652-656
• 全文大小：401K
• ISSN：2155-5435

文摘

A highly efficient synthetic approach to unnatural chiral β-Ar,Ar′-α-amino acid esters bearing two contiguous stereogenic centers has been developed. The first enantioselective 1,6-conjugate addition of glycine Schiff bases to para-quinone methides was achieved using a Cu(CH₃CN)₄BF₄/Ph-Foxap catalytic system (1 mol %). The reaction proceeded smoothly to generate corresponding products in high yields with excellent diastereoselectivities (up to 99:1) and enantioselectivities (up to >99% ee). Subsequent reduction delivered enantiopure unnatural amino alcohols, which were utilized for the synthesis of novel chiral ligands.