A simple, enantiospecific approach to both enantiomers of 1α,25-dihydroxyvitamin D3 A-ring precursors from R-carvone

A simple and direct approach to both enantiomeric series of A-ring derivatives of 1α,25-dihydroxyvitamin D3 and the corresponding 1α,3α-derivatives, starting from the abundantly available R-carvone, is described.