To a suspension of {3-[3-(7-{[2-(trimethylsilyl)ethoxy]methyl}-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-1H-pyrrol-1-yl]azetidin-3-yl}acetonitrile dihydrochloride (3.0 g, 7.3 mmol) in THF (30 mL) were added tert-butyl 4-oxo-1-piperidinecarboxylate (1.4 g, 7.3 mmol), N,N-diisopropylethylamine (6.4 mL, 37 mmol) and sodium triacetoxyborohydride (3.1 g, 15 mmol). The reaction mixture was stirred at room temperature overnight. Brine (20 mL) and EtOAc (20 mL) were added. The organic phase was separated and the aqueous layer was extracted with EtOAc. The combined extracts were dried over sodium sulfate, filtered, and evaporated in vacuo. The residue was purified using combiflash column eluting with 20-50% EtOAc in hexanes to generate tert-butyl 4-{3-(cyanomethyl)-3-[3-(7-{[2-(trimethylsilyl)ethoxy]methyl}-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-1H-pyrrol-1-yl]azetidin-1-yl}piperidine-1-carboxylate as an oil. Yield: 3.37 g (78%); LC-MS: [M+H]+=592.3.
