Reductions of steroidal halohydrins and their esters by tri-n.butyltin hydride; some stereospecific 1.2-migrations of acetoxy- or benzoxy-groups
作者:Sylvestre A. Julia、Robert Lorne
DOI:10.1016/s0040-4020(01)88052-2
日期:1986.1
bearing hydroxy-, acetoxy- or benzoxy-groups in the 3β and 4β or 3β and 6β positions, , , , , , and have been hydrogenolysed with the title reagent to afford the corresponding reduced derivatives. The reduction of 4α-chloro-5β-cholestane-3β, 5-diol 3-benzoate () and 3α-chloro-5α-cholestan-2β-ol acetate gave also the products of simple hydrogenolysis.
Polystyryldiphenylphosphine-halogen complexes are convenient reagents for converting epoxides to halohydrins under mild and non-acidic conditions. The method requires only a filtration and evaporation process for product isolation.
Regioselective formation of chlorohydrins from ring-opening of steroidal epoxides using silica-supported BiCl 3 : A spectral and X-ray crystallographic study
作者:Mahboob Alam、Soonheum Park
DOI:10.1016/j.tetlet.2017.06.035
日期:2017.7
The ring opening of steroidalepoxides are carried out in a regioselective manner using bismuth chloride, ferric chloride, indium chloride, silica supported BiCl3, FeCl3 and InCl3 under mild condition in variable yields. The products obtained were identified by various spectroscopic techniques. The structure of one of the compound has been determined by X-ray diffraction using the direct method and
Bismuth(III) salt-catalyzed Westphalen and “backbone” rearrangements of 5β,6β-epoxysteroids
作者:Rui M.A. Pinto、Jorge A.R. Salvador、Christophe Le Roux、Rui A. Carvalho、Manuela Ramos Silva、Ana Matos Beja、José A. Paixão
DOI:10.1016/j.steroids.2008.01.006
日期:2008.5
bismuth(III) salts as catalysts for the Westphalen and "backbone" rearrangements of 5 beta,6 beta-epoxysteroids is reported. This method is particularly sensitive to changes on solvent, temperature, stereochemistry of starting epoxysteroid, and its substituent at C17. Depending on the reaction conditions, either Westphalen-type or "backbone" rearranged products were obtained, all being 3 beta-acetoxy-6 beta