这份报告描述了在催化不对称曼尼希型反应中前所未有地使用未改性的醛作为供体。N-PMP 保护的 α-亚氨基乙醛酸乙酯与未修饰的脂肪醛的脯氨酸催化反应提供了一种通用且非常温和的进入 β-氨基和 α-氨基酸的对映异构体及其衍生物的高产率和立体选择性。研究的七种醛中的六种产生的产品 ee 值为 99% 或更高。反应的非对映选择性随着醛供体取代基的体积增加而增加,顺序为 R = Me < Et < i-Pr < n-Pent。在研究的五个案例中,实现了出色的顺式立体选择性。此外,相应的手性 β-氨基醛加合物可以很容易地转化为相应的氨基酸衍生物。最重要的是,
An organocatalyst-mediated, asymmetric Mannichreaction in the presence of water without using organic solvents has been developed. A highly reactive siloxytetrazole hybrid catalyst has been developed for the reaction of dimethoxyacetaldehyde, while the sodium salt of siloxyproline is an effective catalyst of alpha-imino glyoxylate. Excellent enantioselectivity can be realized, and the usage of organic
anti-Selective SMP-catalyzed direct asymmetric Mannich-type reactions: synthesis of functionalized amino acid derivatives
作者:Armando Córdova、Carlos F Barbas
DOI:10.1016/s0040-4039(02)01772-0
日期:2002.10
The first (S)-2-methoxymethylpyrrolidine (SMP)-catalyzed direct asymmetricMannich-type reactions of unmodified aldehydes with N-PMP-protected α-imino ethyl glyoxylate are described. The reaction proceeded in a highly anti-selective manner (dr up to 19:1) with enantioselectivities between 74 and 92%.