TiCl 4 catalyzed cleavage of (25R)-22-oxo-23-spiroketals. Synthesis of sapogenins with furostanol and pyranone E rings on the side chain.

•Diastereoselective opening of 22-oxo-23-spiroketals provided the novel furostanols 11a–11d.•Regioselective cleavage of the F ring of 22-oxo-23-spiroketals with TiCl4/Ac2O was attained.•The structure of compounds 11a–d was established using one and bidimensional NMR techniques.•The X-ray analysis of compound 11a confirmed the 22α-hydroxyl orientation at C-23.