Novel Friedel-Crafts Alkylation of Estrogens in the Presence of Anhydrous FeCl 3 or FeCl 3 –Graphite as Catalyst

Summary. The introduction of a tert -butyl group at position 2 of the A ring of estrogens leads to enhanced antioxidant effects. Therefore, a generally applicable and convenient method was developed using FeCl 3 –graphite or anhydrous FeCl 3 as catalysts in the Friedel - Crafts alkylation of estrogens. The rates and yields of the alkylations were lower with FeCl 3 –graphite than with anhydrous FeCl 3 , but the regioselectivity of the former were higher. Both catalysts proved to be more effective than typical AlCl 3 .