Substrate-Induced Diastereoselectivity in the Dimethyldioxirane Epoxidation of Simple Alkenes and Dienes
作者:Amalia Asouti、Lazaros P. Hadjiarapoglou
DOI:10.1055/s-2001-18751
日期:——
Various alkenes and dienes, such as (R)- or (S)-limonene 2, 2-carene 6, 3-carene 8, (R)-α-pinene 10, (S)-α-pinene 12, and endo-dicyclopentadiene 14 were transformed into the corresponding mono- and bis-epoxides by epoxidation with dimethyldioxirane (as an acetone solution). The selectivity observed in these epoxidations is explained by the assumption of hydrogen bonding between bridge protons and the dioxirane.
Regioselective and diastereoselective dimethyldioxirane epoxidation of substituted norbornenes and hexamethyl Dewar benzene
作者:Amalia Asouti、Lazaros P Hadjiarapoglou
DOI:10.1016/s0040-4039(99)02113-9
日期:2000.1
endo-dicyclopentadiene 1, exo-dicyclopentadiene 5, 5-methylenebicyclo[2.2.1]hept-2-ene 8 and hexamethyl Dewar benzene 10 were transformed into the corresponding mono- and bis-epoxides by epoxidation with dimethyldioxirane (as an acetone solution).
Heteropolyoxometalate-catalyzed oxidations of organic compounds such as olefins and cyclic ketones with molecular oxygen in the presence of an aldehyde were examined. Olefins were epoxidized with dioxygen in the presence of 2 equiv of 2-methylpropanal under the influence of a catalytic amount of the mixed heteropolyoxometalate NPV6Mo6 (3) to give the corresponding epoxides in moderate to good yields. This catalytic oxidation method was also applied to the epoxidation of allylic and homoallylic alcohols. In the absence of olefins, the aldehydes were efficiently converted into the corresponding carboxylic acids. In addition, the Baeyer-Villiger oxidation of cyclic ketones was accomplished by using benzaldehyde instead of 2-methylpropanal as the aldehyde.
Oxidation of olefins and alcohols by peroxo-molybdenum complex derived from tris(cetylpyridinium) 12-molybdophosphate and hydrogen peroxide