An unexpected oxidative E/F ring opening in the side chain of steroid sapogenins produced by silica gel supported Jones Reagent.

In contrast with previous results in which the spiroketal side chain of steroid sapogenin has proven to be unreactive to Jones Reagent, treatment these sapogenins with silica gel-supported Jones Reagent triggered the oxidative opening of the spirostanic side chain producing moderate to good yields of sapogenoic acids that bear carbonyl functions at C-16 and C-22 and a C-26 carboxylic group. Based on these findings, a procedure that allows the synthesis of sapogenoic acids minimizing contamination by chromium salts was designed.