title: 4,5-Epoxycholestane-3,6-diols: templates for generating the full set of eight cholestane-3,5,6-triol stereoisomers in multigram scales, but not for a cholestane-3,4,6-triol.
abstract: Cholestane-3beta,5alpha,6beta-triol is an extensively studied biologically important oxysterol. The full set of eight cholestane-3,5,6-triol stereoisomers was synthesised in diastereomerically pure forms by the stereoselective cleavage of eight diastereomerically pure 4,5-epoxycholestane-3,6-diols with LiAlH4, in high yields on multigram scales and without chromatography for most of them. However, applying various reportedly successful combinations of a hydride donor and a Lewis acid to the same substrates under a variety of conditions failed to generate a single unsubstituted cholestane-3,4,6-triol. The products of the eight cholestane-3,5,6-triol stereoisomers will serve as a good probe in the study of biological functions of oxysterols in a biological process.
authors.affiliation: School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
authors.forename: Kejun
authors.initials: K
authors.lastname: Zhao
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Han
mesh_terms: D002776:Cholestanes / Q000737:chemistry*; D002777:Cholestanols / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry*; D006888:Hydroxycholesterols / Q000737:chemistry; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D013237:Stereoisomerism
chemical_list: D002776:Cholestanes; D002777:Cholestanols; D006888:Hydroxycholesterols; D002784:Cholesterol