Highly Enantioselective Direct Alkylation of Arylacetic Acids with Chiral Lithium Amides as Traceless Auxiliaries
作者:Craig E. Stivala、Armen Zakarian
DOI:10.1021/ja205107x
日期:2011.8.10
A direct, highly enantioselective alkylation of arylacetic acids via enediolates using a readily available chiral lithium amide as a stereodirecting reagent has been developed. This approach circumvents the traditional attachment and removal of chiralauxiliaries used currently for this type of transformation. The protocol is operationally simple, and the chiral reagent is readily recoverable.
Kinetic Resolution of Racemic α-Arylalkanoic Acids with Achiral Alcohols via the Asymmetric Esterification Using Carboxylic Anhydrides and Acyl-Transfer Catalysts
enantioselective coupling reaction betweenracemic carboxylic acids and a novel nucleophile, bis(alpha-naphthyl)methanol, to give the corresponding esters with high ee's. This protocol was successfully applied to the production of nonracemic nonsteroidal anti-inflammatory drugs from racemiccompounds utilizing the transacylation process to generate the mixed anhydrides from the acid components with the suitable carboxylic
通过使用非手性醇、芳香族或脂肪族羧酸酐和手性酰基转移催化剂对外消旋 α-取代羧酸进行动力学拆分,可以生产多种光学活性羧酸酯。4-甲氧基苯甲酸酐 (PMBA) 或新戊酸酐与改性苯并四甲醚型催化剂 ((S)-β-Np-BTM) 的组合对于促进外消旋羧酸与新型亲核试剂之间的对映选择性偶联反应最有效, 双(α-萘基)甲醇,得到相应的具有高 ee 的酯。