A Simple, Modular Synthesis of Substituted Pyridines
作者:Songbai Liu、Lanny S. Liebeskind
DOI:10.1021/ja8013743
日期:2008.6.1
A simple, modular method to prepare highly substitutedpyridines is disclosed. The method employs a cascade reaction comprising (1) a novel N-iminative, Cu-catalyzed cross-coupling of alkenylboronic acids at the N-O bond of alpha,beta-unsaturated ketoxime O-pentafluorobenzoates, (2) electrocyclization of the resulting 3-azatriene, and (3) air oxidation affording highly substitutedpyridines in moderate
Preparation of enantiomerically pure (3E)-alkyl-4-(hetero-2-yl)-2-hydroxybut-3-enoates by Candida parapsilosis ATCC 7330 mediated deracemisation and determination of the absolute configuration of (3E)-ethyl-4-(thiophene-2-yl)-2-hydroxybut-3-enoate
作者:T. Vaijayanthi、Anju Chadha
DOI:10.1016/j.tetasy.2007.04.029
日期:2007.5
enoates using Candida parapsilosis ATCC 7330 resulted in the formation of one enantiomer in high enantiomeric excess [up to >99% ee] and isolated yields [up to 79%]. The absolute configuration of the enantiomerically pure (3E)-ethyl-4-(thiophene-2-yl)-2-hydroxybut-3-enoate as determined by 1H NMR of the Mosher esters was found to be (S).
使用假丝酵母假丝酵母ATCC 7330对消旋的(3 E)-烷基-4-(杂-2-基)-2-羟基丁-3-烯酸酯进行消旋,导致形成一种对映体,其对映体过量高[ee高达> 99% ]和孤立的收率[高达79%]。通过Mosher酯的1 H NMR测定,发现对映体纯的(3 E)-乙基-4-(噻吩-2-基)-2-羟基丁-3-烯酸酯的绝对构型为(S)。