Reaction Steps
A mixture of (1S,3aS,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-benzyl 1-isopropyl-5a,5b,8,8,11a-pentamethyl-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 (3.5 g, 5.16 mmol), 4-(methoxycarbonyl)phenylboronic acid (1.206 g, 6.70 mmol), Pd(Ph3P)4 (0.179 g, 0.155 mmol) and sodium carbonate (1.639 g, 15.47 mmol) in dioxane (20 mL) and water (20 mL) was heated up at 90° C. for 2 h. TLC indicated starting material was consumed and a new spot was present. The reaction mixture was purified by biotage with 0-10% ethyl acetate/hexanes to provide the title compound as white solid (3.05 g, 89%). 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 7.92 (d, J=8.24 Hz, 2H), 7.48-7.28 (m, 5H), 7.19 (d, J=7.93 Hz, 2H), 5.28 (dd, J=6.26, 1.68 Hz, 1H), 5.19-5.00 (m, 2H), 3.90 (s, 3H), 2.38-2.20 (m, 3H), 2.11 (dd, J=17.09, 6.41 Hz, 1H), 1.89-1.75 (m, 2H), 1.72-1.61 (m, 2H), 1.53-1.07 (m, 16H), 0.95 (s, 6H), 0.92 (s, 3H), 0.90 (s, 3H), 0.85 (d, J=6.71 Hz, 3H), 0.80 (s, 3H), 0.75 (d, 3H).
