A mixture of tert-butyl 4-[(6-bromo-1-oxo-1,2-dihydroisoquinolin-4-yl)sulfanyl]piperidine-1-carboxylate (Example 58b, 0.353 g) in DMF (5 mL) was treated with (3-bromo-2,2-dimethylpropoxy)(tert-butyl)dimethylsilane (0.452 g) and cesium carbonate (0.785 g). The mixture was stirred at 80° C. for 16 h, then at 90° C. for 16 h. After cooling to room temperature the reaction mixture was partitioned between water (250 mL) and ethyl acetate (3×250 mL). The combined organics were washed with water (3×200 mL) and brine (3×100 mL), dried (MgSO4), filtered and concentrated. The crude product was dissolved in the minimum amount of DCM and purified (SiO2 chromatography, eluting first with isohexane, then 25% diethyl ether/isohexane) to afford the subtitle compound (0.248 g).
