Nitrogen → 5-(Cyclobutylethynyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole

Participants

Reaction Conditions

Reaction Steps

A 100 mL round bottom flask was charged with 5-bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole (6.8 g, 24.2 mmol; Intermediate 1), DMA (30 mL), CuI (0.46 g, 2.4 mmol), Pd(OAc)2 (0.55 g, 2.4 mmol), dppf (1.35 g, 2.4 mmol), Cs2CO3 (11.2 g, 34.4 mmol), and (cyclobutylethynyl)trimethylsilane (5.2 g, 34.1 mmol; Intermediate 48) sequentially while N2 was bubbled through the mixture. The resulting mixture was heated at 80° C. under N2 atmosphere for 2 hours. The reaction mixture was cooled to room temperature, diluted with EtOAc (100 mL) and H2O (100 mL) and filtered. The organic layer of the filtrate was separated, and the aqueous layer was extracted with additional EtOAc (2×50 mL). The combined organic layers were washed with brine (3×100 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified on a silica gel column using 0-10% EtOAc in petroleum ether to afford the title compound as yellow oil (4.8 g, 71%). 1H NMR (DMSO-d6): δ 8.08 (s, 1H), 7.82 (s, 1H), 7.68 (d, 1H), 7.39 (dd, 1H), 5.82 (dd, 1H), 3.89-3.85 (m, 1H), 3.76-3.69 (m, 1H), 3.30-3.24 (m, 1H), 2.39-2.26 (m, 3H), 2.19-2.09 (m, 2H), 2.03-1.84 (m, 4H), 1.75-1.70 (m, 1H), 1.58-1.55 (m, 2H); LCMS: 281 (M+H)+.

Provenance & Evidence