REACTIONS IN DRY MEDIA: REACTIONS OF CHOLESTEROL AND CHOLESTANES ON SILICA BOUND FERRIC CHLORIDE CHOLESTANE-DIACHOLESTENE REARRANGEMENT

Article abstract of DOI:10.1016/0040-4020(81)85029-6

Reaction of cholesterol with silica bound FeCl3 resulted in a mixture of 3β-cholesteryl chloride and dicholesteryl ether.5-cholestene and hydroxy-and halogeno-substituted cholestane derivatives gave on heating at 100 deg C with this reagent a 1:1 mixture of 20-epimeric diacholestenes.The 20(R)-isomer gave with meta-chloroperbenzoic acid 20(R)-α-epoxide, while the 20(S)-gave a mixture of 20(S)-α- and 20(S)-β-epoxides.5α,6β-Dihydrocholestane reacted with the FeCl3/SiO2 under milder conditions (50 deg C) to give 6β-hydroxy-20(R)-diacholestene, which was converted to the 20(R)-diacholestene.