Asymmetric Epoxidation Catalyzed by N-Aryl-Substituted Oxazolidinone-Containing Ketones: Further Evidence for Electronic Effects
摘要:
[GRAPHICS]Ketones containing N-aryl-substituted oxazolidinones have been prepared and investigated for the epoxidation of cis-beta-methylstyrene, styrene, and 1-phenylcyclohexene. The attractive interaction between the phenyl group of the olefin and the oxazolidinone of the catalyst is enhanced by introducing an electron-withdrawing group onto the N-phenyl group of the catalyst. The information obtained gives a better understanding of the ketone-catalyzed epoxidation. In addition, the easy preparation of some of the ketones makes them good candidates for practical use.
Asymmetric Epoxidation Catalyzed by N-Aryl-Substituted Oxazolidinone-Containing Ketones: Further Evidence for Electronic Effects
摘要:
[GRAPHICS]Ketones containing N-aryl-substituted oxazolidinones have been prepared and investigated for the epoxidation of cis-beta-methylstyrene, styrene, and 1-phenylcyclohexene. The attractive interaction between the phenyl group of the olefin and the oxazolidinone of the catalyst is enhanced by introducing an electron-withdrawing group onto the N-phenyl group of the catalyst. The information obtained gives a better understanding of the ketone-catalyzed epoxidation. In addition, the easy preparation of some of the ketones makes them good candidates for practical use.
Highly Enantioselective CH Oxidation of <i>v</i><i>ic</i>-Diols with Shi's Oxazolidinone Dioxiranes
作者:Kavitha Jakka、Cong-Gui Zhao
DOI:10.1021/ol060904a
日期:2006.7.1
[reaction: see text] Through an analogical study of the transition states of CH oxidation and asymmetric epoxidation of terminal alkenes, the first dioxirane-mediated catalytic highlyenantioselective CH oxidation method was realized with Shi's oxazolidinone ketone derivatives. Very good enantioselectivity (up to 92% ee) may be obtained for both asymmetrization of meso vic-diols and kinetic resolution