A Cinchona Alkaloid-Functionalized Mesostructured Silica for Construction of Enriched Chiral β-Trifluoromethyl-β-Hydroxy Ketones over An Epoxidation-Relay Reduction Process.
A cinchona alkaloid-functionalized heterogeneous catalyst is prepared through a thiol-ene click reaction of chiral N-(3,5-ditrifluoromethylbenzyl)quininium bromide and a mesostructured silica, which is obtained by co-condensation of 1,2-bis(triethoxysilyl)ethane and 3-(triethoxysilyl)propane-1-thiol. Structural analyses and characterizations disclose its well-defined chiral single-site active center, and electron microscopy images reveal its monodisperse property. As a heterogenous catalyst, it enables an efficient asymmetric epoxidation of achiral β-trifluoromethyl-β,β-disubstituted enones, the obtained chiral products can then be converted easily into enriched chiral β-trifluoromethyl-β-hydroxy ketones through a sequential epoxidation-relay reduction process. Furthermore, such a heterogeneous catalyst can be recovered conveniently and reused in asymmetric epoxidation of 4,4,4-trifluoro-1,3-diphenylbut-2-enone, showing an attractive feature in a practical construction of enriched chiral β-CF3 -substituted molecules.
Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, No.100 Guilin Rd., Shanghai, 200234, P. R. China.
Cuibao
C
Li
Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, No.100 Guilin Rd., Shanghai, 200234, P. R. China.
Xiaomin
X
Shu
Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, No.100 Guilin Rd., Shanghai, 200234, P. R. China.
Liang
L
Li
Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, No.100 Guilin Rd., Shanghai, 200234, P. R. China.
Genwei
G
Zhang
Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, No.100 Guilin Rd., Shanghai, 200234, P. R. China.
Ronghua
R
Jin
Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, No.100 Guilin Rd., Shanghai, 200234, P. R. China.
Tanyu
T
Cheng
Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, No.100 Guilin Rd., Shanghai, 200234, P. R. China. ghliu@shnu.edu.cn.
Guohua
G
Liu
asymmetric catalysis; heterogeneous catalyst; immobilization; silica; supported catalysts