Diacetoxyiodobenzene-mediated synthesis of unnatural furospirostane sapogenins derived from diosgenin and tigogenin

- Oxidation of steroid sapogenins with NaNO2 afforded the 23-oxo derivatives.
- F-ring contraction of 23-oxosapogenins led to 23-methoxycarbonyl furospirostanes.
- Reduction of contracted the derivatives led to 23-hydroxymethyl furospirostanes.
- X-ray and NMR allowed the unambiguous characterization.