New routes to a-ring substituted estrogens

Estrogens can be regiospecifically functionalized at the position 2 by a few electrophilic reagents. Reactions of estradiol 3-methyl ether-17 beta-acetate with Hg(OAc)2 and BF3 . Et2O/Ac2O allows the preparation of 2-chloromercurio- and 2-organoboron-derivatives respectively. Both the above compounds are useful starting material for easy preparations of 2-catecholestrogens and 2-chloromercurio-derivative can be transformed in other functionalized estrogens. New procedures for the preparation of 2,4-dinitroestrone and 2-nitroestrone are also described.