Synthesis of 13-ethyl-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-17-ol (desogestrel) and its main metabolite 3-oxo desogestrel

Simple, Catalytic Enantioselective Syntheses of Estrone and Desogestrel

“…Catalytic hydrogenation of 14 to the 14,15-dihydro derivative followed by acid-catalyzed transposition of the 8,9-double bond to the 9,11-position generates 15 17 which has been converted by reaction with BH 3 -THF and protection of hydroxyl at C( 17) to the 17R-alcohol 16. 18 Oxidation of 16 to the 11-keto derivative and Peterson methyleneation leads to 17, 18 a latestage intermediate in our recently published route to desogestrel (4). 19 The syntheses of estrone and desogestrel described herein demonstrate the advances in multistep synthesis that can be realized with the widespread use of oxazaborolidinium cationic catalysts of the class represented by 1 and 2.…”

“…The conversion of 14 to desogestrel ( 4 ) can be conducted by a number of previously described routes, one of which is summarized in Scheme . Catalytic hydrogenation of 14 to the 14,15-dihydro derivative followed by acid-catalyzed transposition of the 8,9-double bond to the 9,11-position generates 15 which has been converted by reaction with BH 3 −THF and protection of hydroxyl at C(17) to the 17α-alcohol 16 . Oxidation of 16 to the 11-keto derivative and Peterson methyleneation leads to 17 , a late-stage intermediate in our recently published route to desogestrel ( 4 ) …”