Grignard reagent induced tandem semipinacol rearrangement/ketone addition reaction of 20S-hydroxy-5α-pregnane-16(17)-epoxide
A Grignard reagent induced tandem semipinacol rearrangement/chelation- controlled ketone addition process, which converts 20S-hydroxy-5α- pregnane-16(17)-epoxide into an unusual C20-substituted 17S-pregnane-3S,16R,20S- triol, is described.