A mixture of Intermediate 2 (800 mg, 2.19 mmol) and 3-nitrophenyl boronic acid (366 mg, 2.19 mmol, Sigma Aldrich Company Ltd.) in dioxane (60 ml) was treated with cesium carbonate (1.07 g, 3.29 mmol) and water (20 ml) and degassed with argon for 2 min. Palladium (II) acetate (25 mg, 0.11 mmol) and triphenylphosphine (58 mg, 0.22 mmol) were added and the mixture was stirred at 80° C. under argon for 16 h. The reaction mixture was cooled, then partitioned between ethyl acetate (100 ml) and water (100 ml). The organic layer was separated and dried over Na2SO4 and evaporated in vacuo to give a brown oil (861 mg). This crude oil was purified using flash chromatography to give the title compound as a yellow oil (500 mg, 63%); mass spectrum: (ES−): Found 359 (MH−). C18H20N2O4S requires 360; 1H-NMR (400 MHz, CDCl3) δ 1.38 (6H, m), 2.99 (2H, m), 3.18 (1H, m), 3.38 (2H, m), 4.35 (2H, m), 7.34 (1H, d J=8 Hz), 7.45 (2H, m), 7.60 (1H, m), 7.88 (1H, dd, J=8 Hz and 1 Hz), 8.19 (1H, m), 8.41 (1H, m).
