Catecholborane (7.8 g, 65.4 mmol) in THF (50 mL) was added dropwise to a solution of 40% ethoxyacetylene in hexane (12.8 mL, 72.5 mmol) under nitrogen at 0-5° C. The mixture was stirred for 2 hours at room temperature then heated at 70° C. for 2 hours. The mixture was then cooled to room temperature and a solution of 5-bromo-N-tert-butyl-2-chloropyrimidin-4-amine (10 g, 37.8 mmol) (see Preparation 60) in THF (50 mL) was added. The solution was degassed with argon for about 25 minutes followed by the addition of Pd(PPh3)4 (1.3 g, 1.13 mmol) and powdered sodium hydroxide (4.53 g, 113 mmol). The mixture was heated at 70° C. for 16 hours and then cooled to room temperature. EtOAc (200 mL) was added and the mixture was filtered through a Celite™ pad. The filtrate was evaporated in vacuo and the residue was purified by column chromatography on silica gel (gradient of hexane:EtOAc 93:7 to 90:10) to afford the title compound as a yellow oil in 55% yield, 5.3 g.
