Perfluoroalkylsulfonyl fluoride-mediated abnormal Beckmann rearrangement of steroid 17-oximes with acid-labile groups

A perfluoroalkylsulfonyl fluoride-mediated abnormal Beckmann rearrangement is reported which transforms steroid 17-oximes to the corresponding alkene nitriles regioselectively in good yields. This reaction is rapid (completes in 25 min), mild (proceeds at room temperature) and, most importantly, tolerates various acid-labile functional groups, such as methoxymethyl (MOM), ketal, and methyl enol ether, providing access to molecules that would be difficult to synthesize using existing methods.56