Mechanistic insights and new products of the reaction of steroid sapogenins with NaNO2 and BF3·Et2O in acetic acid

A detailed analysis of the course of the reaction of steroid sapogenins with NaNO2 and BF3·Et2O in acetic acid is presented and some evidences on the involved mechanism are provided. Two new products of the studied reaction were isolated and unambiguously characterized with the aid of NMR and single crystal X-ray diffraction.