Some reactions of 16α,17α-oxido-steroids: a study related to the synthesis of the potent anti-tumor Saponin OSW-1 aglycone

Five 16α,17α-oxido-steroids were subjected to acids, bases and lithium hydroperoxide. Acids caused Wagner–Meerwein-type rearrangement irrespective of the side-chain structure. The 16α,17α-epoxides proved resistant to bases unless a C(22)O group was present; in the case of 22-esters or 22-ketones the oxirane rings were cleaved with base and the corresponding allylic alcohols were formed. The reactions of 16α,17α-oxido-22-carbonyl compounds with lithium hydroperoxide resulted in the epoxide cleavage to the desired 16β,17α-diols which underwent further transformations.