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.
Prevost, Annales de Chimie (Cachan, France), 1928, vol. <10>10, p. 357,378,389 Anm.
作者:Prevost
DOI:——
日期:——
FILMS AND METHODS OF MANUFACTURE
申请人:Synthes USA, LLC
公开号:US20130171410A1
公开(公告)日:2013-07-04
A flexible body comprises a polymer film having a first surface and an opposing second surface. The polymer film has a plurality of apertures extending from the first surface to the second surface and a plurality of raised lips protruding from the first surface such that each of the plurality of apertures is surrounded by one of the plurality of raised lips. A method of producing a polymer film comprises placing a polymer solution into a one sided mold having a plurality of protrusions extending from a bottom of the mold wherein the polymer solution is characterized by a viscosity that inhibits the unaided flow of the polymer throughout the mold; urging the polymer solution around each of the plurality of protrusions; and solidifying the polymer solution.