Asymmetric transfer hydrogenations of β-N-substituted enamino esters with ammonia borane
作者:Weiwei Zhao、Xiangqing Feng、Jing Yang、Haifeng Du
DOI:10.1016/j.tetlet.2019.03.060
日期:2019.4
β-enamino esters is one of the most efficientapproaches for their synthesis. Ammonia borane with low molecular weight, high hydrogen capacity, and good stability, is an ideal hydrogen source for the transfer hydrogenation. However, only a few successful examples have been reported for the asymmetric reduction with ammonia borane. In this work, an asymmetric metal-free transfer hydrogenation of β-N-substituted
Synthesis and Reactivity of New β-Enamino Acid Derivatives: A Simple and General Approach to β-Enamino Esters and Thioesters
作者:Santos Fustero、Marta García de la Torre、Viviana Jofré,、Raquel Pérez Carlón、Antonio Navarro、Antonio Simón Fuentes、Juan Server Carrió
DOI:10.1021/jo9809480
日期:1998.11.1
A new strategy has been developed for the synthesis of several beta-enamino acid derivatives. N,N'-Carbonyldiimidazole has been used as C-acylating agent of methyl ketimines, providing a direct and simple route to new beta-enamino carbonyl imidazole derivatives 2. These derivatives 2 were cleanly and efficiently transformed into beta-enamino esters 4 (X = O) and thioesters 4 (X = S) by reaction with a great variety of alcohols and thiols, including tertiary ones. Alternative and complementary routes to compounds 4 were also investigated. In addition, beta-keto esters 6 have been obtained by mild acid hydrolysis of beta-enamino esters 4.