文献类型：期刊文献

中文题名：钯催化烯丙基取代反应中手性配体的“甲基效应”

英文题名：The "Methyl Effect" in The Enantioselective Allylic Substitution Using Palladium/Chiral Pyridinylmethyl-oxazolines

作者：李枝蓬[1];汤方毅[1];伍新燕[1];周其林[1];陈新滋[2]

机构：[1]华东理工大学精细化工研究所,上海200237;[2]香港理工大学应用生物与化学工程系

年份：2001

卷号：22

期号：12

起止页码：2032

中文期刊名：高等学校化学学报

外文期刊名：Chemical Journal of Chinese Universities

收录：CSTPCD;;Scopus;北大核心:【北大核心2000】；CSCD:【CSCD2011_2012】；

基金：国家重点基础研究发展规划项目基金 (编号 :G2 0 0 0 0 775 0 6 );国家自然科学基金 (批准号 :2 9972 0 2 7);香港理工大学ASD基金资助

语种：中文

中文关键词：不对称催化;烯丙基取代反应;手性吡啶恶唑啉配体;甲基效应;有机合成

外文关键词：Asymmetric catalysis; Allylic substitution; Chiral pyridinyl oxazoline ligand

摘要：In this paper, two types of chiral ligands 1 and 2 containing pyridinyl moiety and oxazolines bridged by a methylene group were investigated in the palladium catalyzed substitution of 1,3 diphenyl 2 propenyl acetate with dimethyl malonate. Ligands 2, which have two methyl groups at the bridged methylene, gave higher enantioselectivities than their unsubstituted analogues 1. This "methyl effect" increased while the substituent on the C 4 in the oxazoline ring was changed from benzyl to tert butyl. Despite of that the "methyl effect" was found in the palladium catalyzed enantioselective allylic substitution, it was obviously significant for assisting rational design of chiral ligands and catalysts in other asymmetric reaction.
In this paper, two types of chiral ligands 1 and 2 containing pyridinyl moiety and oxazolines bridged by a methylene group were investigated in the palladium catalyzed substitution of 1,3 diphenyl 2 propenyl acetate with dimethyl malonate. Ligands 2, which have two methyl groups at the bridged methylene, gave higher enantioselectivities than their unsubstituted analogues 1. This 'methyl effect' increased while the substituent on the C 4 in the oxazoline ring was changed from benzyl to tert butyl. Despite of that the 'methyl effect' was found in the palladium catalyzed enantioselective allylic substitution, it was obviously significant for assisting rational design of chiral ligands and catalysts in other asymmetric reaction.