Tetrahydrofuran → Tert-butyl 4-[5-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrazol-1-yl]piperidine-1-carboxylate

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Reaction Steps

To a solution of tert-butyl 4-(4-iodo-5-methyl-1H-pyrazol-1-yl)piperidine-1-carboxylate (700.0 mg, 1.789 mmol) in THF (20 mL, 300 mmol) at rt was added 1.3 M of isopropylmagnesium chloride in THF (5.5 mL, 7.2 mmol), and the mixture was stirred for 1 h. The reaction was quenched with 2-methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.5 mL, 8.9 mmol), and allowed to stir at rt for 2 h. Water was added, and the organic solvent was removed in vacuo. The material was extracted with DCM and water. The organic layer was dry-loaded onto silica gel for column chromatography, eluting with 10% EtOAc/heptane. The fractions containing the pure product were concentrated in vacuo to afford the title compound as a white solid. 1H NMR (400 MHz, CD3OD): δ=1.30 (s, 12H), 1.48 (s, 9H), 1.84 (d, J=10.4 Hz, 2H), 1.99 (dtd, J=12.6, 12.3, 12.3, 4.5 Hz, 2H), 2.47 (s, 3H), 2.94 (br. s., 2H), 4.21 (d, J=13.6 Hz, 2H), 4.30-4.42 (m, 1H), 7.57 (s, 1H). MS (ES+): m/z=391.26/392.26/393.27 (50/100/50) [MH+]. HPLC: tR=1.70 min (polar—3 min, UPLC-ACQUITY).

Provenance & Evidence