Short synthesis of 16β-hydroxy-5α-cholestane-3,6-dione a novel cytotoxic marine oxysterol

The first and short synthesis of 16β-hydroxy-5α-cholestane-3,6-dione 1 a metabolite from marine algae, has been achieved in six steps from readily available diosgenin 5. Selective deoxygenation of primary alcohol of triol 6 has been accomplished in one step using Et3SiH and catalytic amount of B(C6F5)3 to produce compound 9 in high yield. Oxidation of 11 with PCC, allowed the introduction of 3,6-ene-dione functionality, and further catalytic hydrogenation and deprotection furnished the 3,6-diketo steroid 1.

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