Catalytic Parallel Kinetic Resolution under Homogeneous Conditions
作者:Trisha A. Duffey、James A. MacKay、Edwin Vedejs
DOI:10.1021/jo100695z
日期:2010.7.16
Two complementary chiral catalysts, the phosphine 8d and the DMAP-derived ent-23b, are used simultaneously to selectivelyactivate a mixture of two different achiral anhydrides as acyl donors under homogeneous conditions. The resulting activated intermediates 25 and 26 react with the racemic benzylic alcohol 5 to form enantioenriched esters (R)-24 and (S)-17 by fully catalyticparallelkinetic resolution
两种互补的手性催化剂,膦8d和 DMAP 衍生的ent - 23b,同时用于在均相条件下选择性活化作为酰基供体的两种不同非手性酸酐的混合物。所得活化中间体25和26与外消旋苯甲醇5反应,通过完全催化平行动力学拆分(PKR)形成对映体富集的酯( R ) -24和( S ) -17。对于 PKR 过程,芳酰基酯 ( R )- 24以近乎理想的对映选择性获得,但 ( S)- 17被大约污染。8% 的次要对映异构体 ( R ) -17来自第二个途径,通过形成混合酸酐27并在8d激活。
Water-Soluble Acylating Agents: Preparation of 2-Acylthio-1-alkylpyridinium Salts and Acylation of Phenols, Acids, and/or Amines with These Salts in an Aqueous Phase
Reaction of phenols, amines, and acids with 2-benzoylthio-1-methylpyridiniumchloride prepared in situ from benzoyl chloride and 1-methyl-2(1H)-pyridinethione, afforded the corresponding benzoyl derivatives in good yields. In the reaction of p-nitrophenol, even a catalytic amount of 1-methyl-2(1H)-pyridinethione proved to be effective. Similar reactions of p-nitrophenol with isobutyryl chloride and acetyl
Phase managed organic synthesis 2. A new polymer assisted synthesis of acid anhydrides.
作者:Wilmer K. Fife、Zhi-dong Zhang
DOI:10.1016/s0040-4039(00)85100-x
日期:1986.1
A solid-phase copolymer of 4-vinylpyridine is shown to be a highly effective reagent/ catalyst for the synthesis of acid anhydrides from mixtures containing equimolar quantities of carboxylic acids and acid chlorides. The process may be carried out in batch or column mode.