A highly efficient, stereoselective oxyfunctionalization of unactivated carbons in steroids with dimethyldioxirane†

Oxyfunctionalization of unactivated methine carbon atoms with dimethyldioxirane (DMDO) is studied for various substituted steroids related to the 5β-cholane and 5α-cholestane series. A highly efficient, stereoselective, one-step remote oxidation of specific methine carbons is attained by DMDO oxidation under mild conditions to give a variety of novel mono- and dihydroxylated steroids. The reactivity and site selectivity of remote oxyfunctionalization is influenced significantly by the structural and steric environments as well as by the degree of electron density of the target methine carbon atoms in the molecules. The non-enzymatic procedure may be usefully applied to effective and short-step syntheses of bioactive steroids.