sulfur) is shown to be strongly dependent on the aryl substituent. By contrast, the analogous reaction of optically pure compounds 6 with 3-nitro-1,2,4-triazole led to racemic arenesulfonimidoyl nitrotriazoles 9. Opticallyactivecompounds of this type, (S)-9f (ee 99%) and (R)-9f (ee 92%). were obtained by semi-preparative chiral HPLC. The opticallyactive arenesulfonimidoyl imidazolium salt (R S,R C-)-8j
Activation of hydrogen peroxide for asymmetric epoxidation by chiral arenesulfonimidoylimidazoles
作者:Ralph Kluge、Heiko Hocke、Manfred Schulz
DOI:10.1016/s0957-4166(97)00283-8
日期:1997.8
Different types of olefins were oxidized by using the chiral (arenesulfonimidoyl)imidazoles 3a,b and H2O2 in the presence of 2N NaOH or K2HPO4. The corresponding epoxides were isolated in moderate to good yields. Cis- and trans-olefins were converted stereospecifically (retention of the configuration). Enantiomeric excesses up to 42% were obtained.
在2N NaOH或K 2 HPO 4存在下,通过使用手性(芳烃磺酰亚胺基)咪唑3a,b和H 2 O 2氧化不同类型的烯烃。以中等至良好的产率分离出相应的环氧化物。将顺式和反式烯烃立体定向转化(保留构型)。获得了高达42%的对映体过量。