Asymmetric Friedel–Crafts Alkylation of α-Substituted β-Nitroacrylates: Access to β2,2-Amino Acids Bearing Indolic All-Carbon Quaternary Stereocenters

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• 作者：Jian-Quan Weng ; Qiao-Man Deng ; Liang Wu ; Kai Xu ; Hao Wu ; Ren-Rong Liu ; Jian-Rong Gao ; Yi-Xia Jia
• 刊名：Organic Letters
• 出版年：2014
• 出版时间：February 7, 2014
• 年：2014
• 卷：16
• 期：3
• 页码：776-779
• 全文大小：297K
• ISSN：1523-7052

文摘

A highly enantioselective Friedel鈥揅rafts alkylation reaction of indoles with acyclic 伪-substituted 尾-nitroacrylates is developed under the catalysis of Ni(ClO₄)₂鈥揵isoxazoline complex at 1 mol % catalyst loading, affording chiral indolic 尾-nitroesters bearing all-carbon quaternary stereocenters in excellent yields and ees of up to 97%. Transformation of one of the products to 尾^2,2-amino ester and tetrahydro-尾-carboline through nitro reduction and sequential Pictet鈥揝pengler cyclization was exemplified.