Diastereoselective Epoxidation of Cyclohexene Derivatives by Dioxiranes Generated in Situ. Importance of Steric and Field Effects
作者:Dan Yang、Guan-Sheng Jiao、Yiu-Chung Yip、Man-Kin Wong
DOI:10.1021/jo9821978
日期:1999.3.1
In this paper, diastereoselective epoxidation of substituted cyclohexenes (substrates 1-7) by dioxiranes generated in situ from ketones and Oxone was systematically investigated. The results revealed that the diastereoselectivity was determined by the steric and field effects of both dioxiranes and substrates, and high diastereoselectivity can be achieved by tuning the ketone structure. Among the ketones
Highly Diastereoselective Epoxidation of Allyl-Substituted Cycloalkenes Catalyzed by Metalloporphyrins
作者:Wing-Kei Chan、Peng Liu、Wing-Yiu Yu、Man-Kin Wong、Chi-Ming Che
DOI:10.1021/ol0496475
日期:2004.5.1
Highly diastereoselectiveepoxidations of allyl-substituted cycloalkenes including allylic alcohols, esters, and amines using sterically bulky metalloporphyrins [Mn(TDCPP)Cl] (1) and [Ru(TDCPP)CO] (2) as catalysts have been achieved. The "1 + H(2)O(2)" and "2 + 2,6-Cl(2)pyNO" protocols afforded trans-epoxides selectively in good yields (up to 99%) with up to >99:1 trans-selectivity.
Role of Amine Modifiers in the Epoxidation of Allylic Alcohols with a TiO2–SiO2 Aerogel
作者:Marco Dusi、Tamas Mallat、Alfons Baiker
DOI:10.1006/jcat.1999.2582
日期:1999.10
under oxidizing reaction conditions. The method of amine addition was applied also to the epoxidation of other linear and cyclic allylic alcohols and 2-hexene. The scope of this method seems to be limited to epoxidation of allylic alcohols. A model for the interaction of allylic alcohol, amine, and peroxide with the Ti active site is proposed, which can interpret the enhanced selectivity and suppressed
Novel amine-modified TiO2–SiO2 aerogel for the demanding epoxidation of substituted cyclohexenols
作者:Marco Dusi、Christian A. Müller、Tamas Mallat、Alfons Baiker
DOI:10.1039/a808374f
日期:——
Amine additives provided high selectivity (up to 98%) in the epoxidation of sensitive alkyl-substituted cyclohexenols with a TiO2âSiO2 aerogel and ButOOH; heterogenization of the catalyst system resulted in a new bifunctional catalyst.
Oxygen transfer reactions from an Oxaziridinium tetrafluoroborate salt to Olefins
作者:Xavier Lusinchi、Gilles Hanquet
DOI:10.1016/s0040-4020(97)00890-9
日期:1997.10
Oxaziridinium efficiently epoxidises olefins. It reacts as an electrophilic reagent and does not transfer its oxygen to deactivated double-bonds or carbonyl functions. Epoxidation of cyclic allylic acetates shows a remarkable diastereoselectivity leading to the syn isomer. We propose that the epoxidation reaction proceeds through a one-step process.