An efficient procedure for the regiospecific preparation of D-homo-steroid derivatives.

alpha-Diazo-beta-hydroxy esters 3, obtained by condensation of ketones 1 with ethyl diazo(lithio)acetate 2, are efficiently converted into the corresponding beta-ketoesters 4 by exposure to dirhodium (II) tetraacetate. Application of this two-step sequence to 3 beta-acetoxy-5-androstene-17-one 5b and to 3-acetoxy estrone 10b afforded regiospecifically and in very high overall yield the corresponding ethyl 17a-oxo-D-homo-steroid-17-carboxylates 7a,b and 12a,b, which were decarboalkoxylated to give, respectively, 3 beta-hydroxy-D-homo-5-androstene-17a-one 8 and D-homoestrone 13.