Chlorination of 20-Oxopregnanes with the Manganese Dioxide–Chlorotrimethylsilane/Acetyl Chloride System: A Simple Approach Towards the Construction of the Corticosteroid Side Chain
Abstract
C-21 chlorination of 20-oxosteroids using the system MnO2 (excess)–TMSCl or MnO2 (excess)–AcCl in acetic acid medium as well as an example of a Wagner–Meerwein rearrangement of 17α-chloro-20-oxopregna-3β-yl acetate to 17-β-methyl-18-nor-17α-pregn-13-en-3β-yl acetate have been demonstrated.