1,6-dibromohexa-2,4-diene 在
氧气 、 Rose Bengal bis(triethylammonium) salt 作用下,
以
二氯甲烷 为溶剂,
反应 6.0h,
以63%的产率得到(3S,6R)-3,6-di(bromomethyl)-3,6-dihydro-1,2-dioxin
参考文献:
名称:
Osmium Catalyzed Dihydroxylation of 1,2-Dioxines: A New Entry for Stereoselective Sugar Synthesis
摘要:
A series of 3,6-substituted 3,6-dihydro-1,2-dioxines were dihydroxylated with osmium tetroxide to furnish 1,2-dioxane-4,5-diols (peroxy diols) in yields ranging from 33% to 98% and with de values not less than 90%. The peroxy diols were then reduced to generate a stereospecific tetraol core with R, R, S, S or "allitol" stereochemistry. The peroxy diols and their acetonide derivatives were also ring-opened with Co(II) salen complexes to give novel hydroxy ketones in 77-100% yield, including the natural sugar psicose. Importantly, preliminary work on the catalytic asymmetric ring-opening of meso-peroxy diols using the Co(II) Jacobsens's catalyst indicates that asymmetric sugar synthesis from 1,2-dioxines is possible.