Catalytic Enantioselective
Electrophilic Aminations of Acyclic α-Alkyl β-Carbonyl
Nucleophiles
作者:Li Deng、Xiaofeng Liu、Bingfeng Sun
DOI:10.1055/s-0029-1217334
日期:——
Highly enantioselective aminations of acyclic α-alkyl β-keto thioesters and trifluoroethyl α-methyl α-cyanoacetate (12) with as low as 0.05 mol% of a bifunctional cinchona alkaloid catalyst were established. This ability to afford high enantioselectivity for the amination of α-alkyl β-carbonyl compounds renders the 6′-OH cinchona alkaloid-catalyzed amination applicable for the enantioselective synthesis of acyclic chiral compounds bearing N-substituted quaternary stereocenters. The synthetic application of this reaction is illustrated in a concise asymmetric synthesis of α-methylserine, a key intermediate previously utilized in the total synthesis of a small molecule immunomodulator, conagenin.
高对映选择性的环外α-烷基β-酮硫酸酯和三氟乙基α-甲基α-氰基乙酸酯(12)的胺化反应,采用低至0.05摩尔%的双功能金鸡纳碱催化剂得到。对α-烷基β-酮化合物的高对映选择性胺化能力,使得6'-羟基金鸡纳碱催化的胺化反应适用于具有N取代四面体立体中心的非环状手性化合物的对映选择性合成。此反应的合成应用在α-甲基丝氨酸的简明不对称合成中得到了说明,α-甲基丝氨酸是之前用于小分子免疫调节剂conagenin的全合成中的关键中间体。