Asymmetric hetero Diels–Alder reaction using chiral cationic metallosalen complexes as catalysts
作者:Kohsuke Aikawa、Ryo Irie、Tsutomu Katsuki
DOI:10.1016/s0040-4020(00)01048-6
日期:2001.1
–chromium(III) complexes served as the catalysts for asymmetric heteroDiels–Alderreaction of Danishefsky'sdiene with aldehydes, achieving high enantioselectivity (up to 97% ee at 0°C). The reactions of aldehydes bearing no precoordinating functional group were well effected by using (R,R)-complexes as catalysts, while those of aldehydes bearing a precoordinating functionality were better effected by
Highly asymmetric hetero-Diels–Alder reaction using helical silica-supported Mn(III)-salen catalysts
作者:Le Li、Yu Li、Di Pang、Fei Liu、Aqun Zheng、Guangbin Zhang、Yang Sun
DOI:10.1016/j.tet.2015.08.045
日期:2015.10
Helical silica were prepared and functionalized by Mn(III)-salen complexes in order to catalyze asymmetric hetero-Diels Alder reactions. Characterizations revealed doping of sodium lactate facilitated porosity, hydrolysis resistance and chiral configuration of silica matrix. Catalysis revealed the combination of Mn(III)-salen with helical silica had excellent chiral induction. Major product configuration was affected by temperature and solvent. Loading imidazolium ionic liquid as solvent improved both enantioselectivity and catalyst recycling. (C) 2015 Elsevier Ltd. All rights reserved.
Silica-based helical rod supporting guanosine compounds catalyzed asymmetric hetero-Diels–Alder reaction
作者:Le Li、Guangbin Zhang、Benhua Huang、Lin Ren、Aqun Zheng、Junjie Zhang、Yang Sun
DOI:10.1016/j.catcom.2015.01.016
日期:2015.4
A series of silica-based helical rods were prepared and functionalized for immobilization of guanosine compounds in catalytic asymmetric hetero-Diels-Alder reaction. Nitrogen physisorption, electron microscopy and amino acid adsorption revealed that helical rod has a hierarchical structure including morphology and internal channels, and doping of sodium lactate facilitates porosity and internal chirality of synthetic rods. Catalysis revealed that guanosine derivatives were catalytically active, combination of guanosine with L-sodium lactate-doped rod was more enantioselective than that with zero- or D-sodium lactate-doped samples, and recycling of supported Schiff-base-guanosine was stable during six cycles. (C) 2015 Elsevier B.V. All rights reserved.
Chromium-Thiophene-salen-Based Polymers for Heterogeneous Asymmetric Hetero-Diels–Alder Reactions
proved to beefficient catalysts for promoting asymmetrichetero-Diels–Alderreactions with good activities and high enantioselectivities (up to 88 % ee). These complexes were successfully electropolymerized to give chiral polymers as insoluble powders for use in asymmetricheterogeneous catalysis. When engaged in successive hetero-Diels–Alderreactions, they afforded the expected products in high yield