Triphenylphosphine → tert-butyl (2S)-2-[(4-bromo-1H-pyrazol-1-yl)methyl]morpholine-4-carboxylate

Participants

Reaction Steps

Tetrahydrofuran was added to a mixture of (S)-tert-butyl 2-(hydroxymethyl)morpholine-4-carboxylate (250 mg, 1.15 mmol), 4-bromo-1H-pyrazole (186 mg, 1.27 mmol), di-tert-butyl azodicarboxylate (530 mg, 2.30 mmol), and triphenylphosphine resin (3 mmol/g loading, 601 mg, 2.30 mmol) under argon. The resulting suspension was stirred for 8 days and then filtered through CELITE. The supernatant was concentrated under reduced pressure, and the residue was purified by chromatography on silica gel (5-100% ethyl acetate/hexanes) to afford tert-butyl (2S)-2-[(4-bromo-1H-pyrazol-1-yl)methyl]morpholine-4-carboxylate. ESI calc'd. for C9H13BrN3O3 [M+H t-Bu]+ 289 and 291. found 289 and 291. 1H NMR (500 MHz, CDCl3) δ 7.49 (s, 1H), 7.46 (s, 1H), 4.22-4.08 (m, 2H), 4.04-3.78 (m, 3H), 3.76-3.69 (br s, 1H), 3.52-3.46 (m, 1H), 2.99-2.82 (br s, 1H), 2.63-2.51 (br s, 1H), 1.45 (s, 9H).

Provenance & Evidence