Total synthesis of 14α-hydroxyestrone 3-methyl ether

Abstract

Total synthesis of 14α-hydroxyestrone 3-methyl ether (5) was achieved by the thermolysis of 2-[2-(1,2-dihydro-4-methoxybenzocyclobuten-1-yl)ethyl] 3-hydroxy-2-methyl-3-vinylcyclopentan-1-one (27), obtained by Grignard reaction of 2-[2-(1,2-dihydro-4-methoxybenzocyclobuten-1-yl)ethyl]-2-methylcyclopentane-1,3-dione (26) with vinylmagnesium bromide. An alternative synthesis of (5) started from authentic 14-dehydroestradiol bis(t-butyldimethylsilyl) ether (28) and proceeded through estradiol-14α,15α-epoxide 3-methyl 17β-t-butyldimethylsilyl bisether (31).