Reaction Steps
Potassium vinyltrifluoroborate (2.0 eq.), Et3N (2.0 eq.) and PdCl2(dppf)-DCM adduct (0.05 eq.) were sequentially added to a 0.12 M solution of methyl (4R)-4-[(3′-bromobiphenyl-3-yl)methoxy]-1-{(2S)-2-[(tert-butoxycarbonyl)amino]-2-cyclohexylacetyl}-L-prolinate 106 in EtOH. The reaction mixture was stirred with heating at reflux for 3 h then it was cooled down to RT and diluted with H2O:EtOAc. The phases were separated and the organic layer was washed with brine, dried (Na2SO4) and evaporated under reduced pressure. The residue was purified by flash chromatography (SiO2, PE:EtOAc=8:2) to afford the title compound 107 (72%) as a foam. 1H NMR (400 MHz, DMSO-d6, 300 K) δ 7.75 (s, 1H), 7.71-7.61 (m, 2H), 7.59 (d, J 7.3, 1H), 7.56-4.43 (m, 3H), 7.39 (d, J 7.3, 1H), 6.94 (d, J 8.6, 1H), 6.86 (dd, J 17.7, 10.9, 1H), 5.98 (d, J 17.7, 1H), 5.36 (d, J 10.9, 1H), 4.66 (d, J 11.7, 1H), 4.58 (d, J 11.7, 1H), 4.36 (t, J 8.6, 1H), 4.32 (bs, 1H), 4.19 (d, J 10.9, 1H), 4.15-4.07 (m, 1H), 3.73-3.66 (m, 1H), 3.65 (s, 3H), 2.46-2.35 (m, 1H), 2.07-1.98 (m, 1H), 1.82-1.57 (m, 6H), 1.42-1.36 (m, 1H), 1.34 (s, 9H), 1.20-1.12 (m, 2H), 1.07-0.94 (m, 2H). MS (ES+) m/z 577 (M+H)+
