Triphenylphosphine → [2-(2,6-Difluoro-3-nitrophenoxy)ethyl]carbamic acid tert-butyl ester

Participants

Reaction Steps

To a solution of 2,6-difluoro-3-nitrophenol (248 mg, 1.416 mmol) and triphenylphosphine (558 mg, 2.127 mmol) in THF (10 mL) was added a solution of (2-hydroxyethyl)carbamic acid tert-butyl ester (274 mg, 1.70 mmol) in THF (2 mL). The mixture was cooled in an ice bath and a solution of diethyl azodicarboxylate (372 mg, 2.127 mmol) in THF (2 mL) was added over 5 min. The reaction was removed from the ice bath after 5 min and stirred at RT for 2 h, then concentrated in vacuo. The resulting residue was purified by column chromatography (Si—PCC, eluant 30-40% EtOAc in cyclohexane) affording the title compound as a colourless gum (483 mg, quantitative). 1H NMR (CDCl3, 300 MHz): 7.84 (1H, ddd, J=9.5, 7.8, 5.3 Hz), 7.05 (1H, dt, J=9.9, 2.2 Hz), 5.05 (1H, bs), 4.26 (2H, t, J=5.0 Hz), 3.52 (2H, q, J=5.4 Hz), 1.45 (9H, s)

Provenance & Evidence