Reduction of 17.alpha.-hydroxy-20-keto steroids: convenient synthesis of (E)-3.beta.-hydroxy-5,17(20)-pregnadiene 3-pivaloate and (Z)-3.beta.,16.alpha.-dihydroxy-5,17(20)-pregnadiene 3-pivaloate
Reduction of 17.alpha.-hydroxy-20-keto steroids: convenient synthesis of (E)-3.beta.-hydroxy-5,17(20)-pregnadiene 3-pivaloate and (Z)-3.beta.,16.alpha.-dihydroxy-5,17(20)-pregnadiene 3-pivaloate