Arabinose-Derived Ketones as Catalysts for Asymmetric Epoxidation of Alkenes
作者:Tony K. M. Shing、Gulice Y. C. Leung、To Luk
DOI:10.1021/jo050928f
日期:2005.9.1
Readily available arabinose-derived ketones, containing a tunable butane-2,3-diacetal as the steric blocker, displayed increasing enantioselectivity (up to 90% ee) with the size of the acetal alkyl group in catalytic asymmetricepoxidation of trans-disubstituted and trisubstituted alkenes. The stereochemical communication between our ketonecatalysts and the alkene substrates is mainly due to steric
An Efficient Catalytic Asymmetric Epoxidation Method
作者:Zhi-Xian Wang、Yong Tu、Michael Frohn、Jian-Rong Zhang、Yian Shi
DOI:10.1021/ja972272g
日期:1997.11.1
This article describes a highly effective catalyticasymmetricepoxidation method for olefins using potassium peroxomonosulfate (Oxone, Dupont) as oxidant and a fructose-derived ketone (1) as catalyst. High enantioselectivies have been obtained for trans-disubstituted and trisubstituted olefins which can bear functional groups such as tributylsilyl ether, acetal, chloride, and ester. The enantiomeric
Chemo- and stereoselectivity in the ring-openingreaction of epoxides with a reagent prepared from allylmagnesium halide and chlorotitanium triphenoxide is described. It has been proven that the allylating reagent can also be used for the reaction of epoxides bearing a tert-butyl ester, amide, or acetal moiety, and that the epoxide cleavage regioselectively takes place at the more substituted carbon
Conversion of Aziridinemethanol Sulfonate Esters to Allylic Amines via Tellurium Chemistry<sup>1</sup>
作者:Aurora S. Pepito、Donald C. Dittmer
DOI:10.1021/jo962024n
日期:1997.11.1
Sulfonate esters of aziridinemethanols are converted to allylic amines by treatment with telluride ion obtained by reduction of elemental tellurium. In the course of the reaction, tellurium(0) is reformed and may be reused, thus removing the need to dispose of a key reagent. The telluride reaction yields optically active allylic amines from optically active aziridinemethanols. In contrast to many ring-openings
Asymmetric epoxidation using hydrogen peroxide (H2O2) as primary oxidant
作者:Lianhe Shu、Yian Shi
DOI:10.1016/s0040-4039(99)01814-6
日期:1999.12
High enantioselectivities have been obtained for asymmetricepoxidation of olefins using a fructose-derived chiral ketone as catalyst and hydrogenperoxide as primary oxidant.