N-Allylaniline → (S)-tert-butyl 1-(allyl(phenyl)amino)-1-oxopent-4-en-2-ylcarbamate

Participants

Reaction Conditions

Reaction Steps

A solution of N-propylphosphonic acid anhydride cyclic trimer (50% reagent in EtOAc solution, 1.26 mL, 2.14 mmol) was added to a degassed solution of (S)-2-(tert-butoxycarbonylamino)pent-4-enoic acid (230 mg, 1.07 mmol), N-allylaniline (142 mg, 1.07 mmol), and Hunig's Base (0.560 mL, 3.21 mmol) at 0° C. The reaction mixture was stirred under argon for 2 min at 0° C. and then warmed to rt and stirred for 1 hr. The reaction mixture was diluted with EtOAc, washed with saturated aqueous NaHCO3 and saturated aqueous NaCl, dried over Na2SO4, filtered and concentrated. The crude product was purified using silica gel chromatography (ISCO system) eluting with a gradient of 0-30% EtOAc/Hex to give (S)-tert-butyl 1-(allyl(phenyl)amino)-1-oxopent-4-en-2-ylcarbamate (195 mg, 0.590 mmol, 55.2% yield) as a colorless oil. 1H NMR (400 MHz, CDCl3) δ ppm 7.43 (t, J=7.4 Hz, 2H), 7.36 (t, J=7.3 Hz, 1H), 7.24 (d, J=7.5 Hz, 2H), 5.91-5.78 (m, 1H), 5.63-5.49 (m, 1H), 5.23 (d, J=8.4 Hz, 1H), 5.18-5.05 (m, 2H), 5.05-4.94 (m, 2H), 4.43-4.19 (m, 3H), 2.33-2.23 (m, 1H), 2.20-2.08 (m, 1H), 1.45 (s, 9H).

Provenance & Evidence