Abnormal Beckmann fragmentation/ring closing metathesis route for preparation of 18-nor-Delta-androgens and their 18-nor-13,17-epoxide derivatives.

The synthesis of Delta(13,(17))-androgens and the structurally related 13,17-epoxides is described. The synthetic route involves cleavage of 17-ketosteroids by an abnormal Beckmann rearrangement, modification of the D-ring cleavage product to obtained an intermediate tricyclic diene and ring closing metathesis of the diene to the Delta(13,(17))-androgen. (3alpha,5alpha)-Androst-13(17)-en-3-ol and the derivative 13alpha,17alpha- and 13beta,17beta- epoxides were prepared by this route.