Chemoselective hydrogenation of 17α-hydroxy-6-methylen-pregna-4,9(11)-diene-3,20-dione. Synthesis of fluorometholone

The development of an efficient hydrogenation method of 17α-hydroxy-6-methylen-pregna-4,9(11)-diene-3,20-dione by using wet (10%) Pd on carbon and triethylamine led us to the corresponding 6α-methyl-pregnane in good yield. This chemoselective process allowed us to set up a large-scale procedure for the synthesis of the ophthalmic drug fluorometholone with 45% overall yield.