Synthesis of some novel D-ring-fused dioxa- and oxazaphosphorinanes in the estrone series

New types of P-heterocyclic-fused steroids, such as dioxa- and oxazaphosphorinane derivatives, were synthetized from estrone-1,3-dihydroxy and 1,3-aminoalcohol precursors by cyclization with phenylphosphonic dichloride.