3-Fluoro-4-(methoxycarbonyl)benzeneboronic acid → methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(chlorocarbonyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)-2-fluorobenzoate

Participants

Reaction Steps

The title compound was prepared from (1R,3aS,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-benzyl 5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-9-(trifluoromethylsulfonyloxy)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysene-3a-carboxylate (Intermediate 3) following the above described procedures for the Suzuki coupling (as described for intermediate 4, but using 3-fluoro-4-(methoxycarbonyl)phenylboronic acid as the reactant); deprotection of the C-28 acid (as described for intermediate 5 and 6) and conversion into acid chloride (as described for intermediate 7). The crude material was taken to the next step without further purification. LCMS: m/e 605.39 (M−Cl+OMe+H)+, 4.12 min (method 1).

Provenance & Evidence