Sterically Modified Chiral (Salen)Cr(III) Complexes - Efficient Catalysts for the Oxo-Diels-Alder Reaction between Glyoxylates and Cyclohexa-1,3-diene
作者:Janusz Jurczak、Wojciech Chaadaj、Piotr Kwiatkowski
DOI:10.1055/s-2006-951535
日期:——
A group of chiral [(salen)Cr(III)] + BF 4 - complexes, with enhanced steric hindrance in 3,3'-positions of salicylidene moiety, has been synthesized and applied for the oxo-Diels-Alder reaction of alkyl glyoxylates with cyclohexa-1,3-diene. A readily accessible complex that bears bulky adamanthyl substituents revealed its potential, leading to the cycloadducts with excellent selectivity (up to endolexo
合成了一组手性 [(salen)Cr(III)] + BF 4 - 配合物,在水杨基部分的 3,3'-位具有增强的空间位阻,并应用于烷基乙醛酸酯的氧代-Diels-Alder 反应与环己-1,3-二烯。带有庞大金刚烷基取代基的易于获得的配合物显示出其潜力,导致环加合物具有出色的选择性(高达内链烯 99:1,98% ee),比经典的 Jacob-sen 催化剂要好得多。