A microwave tube is charged with 8-Bromo-2-chloro-quinoxaline (Step 1.4, 1 g, 4.11 mmol), 4-[4-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-pyrazol-1-yl]-piperidine-1-carboxylic acid tert-butyl ester (1.74 g, 3.70 mmol), K3PO4 (2.67 g, 12.3 mmol) and of PdCl2(PPh3)2 (88.2 mg, 0.123 mmol). After several cycles of vacuum/purge with argon, a mixture of 5 ml of DMA and 220 μl deionized water is added. The reaction mixture is then heated to 80° C. for 3 h. After cooling, the suspension is poured onto de-ionized water and diluted with EtOAc. The phases are separated and the aqueous phase re-extracted twice with EtOAc. The combined organic phases are washed with saturated brine and dried over Na2SO4. After filtration, the mixture is concentrated in vacuo. The residue is purified by chromatography on a 80 g silica gel column on a Combiflash Companion™ (Isco Inc.) apparatus (gradient hexanes:EtOAc from 1:0=>0:1) to afford the title compound as a yellow foam, Rt=1.350 min (Acquity HPLC BEH C18, 2.1×50 mm, 1.7 micron, detection 215 nM, 0.1 min 2% CH3CN in H2O, 2% to 100% CH3CN in H2O in 1.5 min, 0.4 min 100% CH3CN+0.1% TFA, flow rate 1.0 ml/min); MS: 458 (M+1, 79Br)+.
