Into a 100-mL 3-necked round-bottom flask purged and maintained under an inert atmosphere of nitrogen, was placed tert-butyl (2R)-2-([4-amino-3-iodo-1H-pyrazolo[3,4-d]pyrimidin-1-yl]methyl)pyrrolidine-1-carboxylate (300 mg, 0.68 mmol, 1.00 equiv), prepared as described in Example 1 except in the Mitsunobu reaction using (R)-tert-butyl 2-(hydroxymethyl)pyrrolidine-1-carboxylate instead of (S)-tert-butyl 3-hydroxypiperidine-1-carboxylate, 2-[4-(3-fluorophenoxy)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (254 mg, 0.81 mmol, 1.20 equiv), tetrakis(triphenylphosphane)palladium (47 mg, 0.04 mmol, 0.06 equiv), ethylene glycol dimethyl ether (50 mL), sodium carbonate (180 mg, 1.70 mmol, 2.50 equiv), and water (10 mL). The resulting solution was stirred for 12 h at 80° C. in an oil bath. The resulting mixture was concentrated under vacuum and extracted with dichloromethane. The organic layers were combined, dried and concentrated under vacuum. The residue was loaded on a silica gel column and eluted with dichloromethane/methanol (50/1) to give 0.27 g (79%) of tert-butyl (2R)-2-([4-amino-3-[4-(3-fluorophenoxy)phenyl]-1H-pyrazolo[3,4-d]pyrimidin-1-yl]methyl)pyrrolidine-1-carboxylate as a brown solid.
