Triethylamine → [2-[2-(Tert-butyl-dimethyl-silanyloxymethyl)-pyrrolidine-1-carbonyl]-4,5-dimethoxy-phenyl]-carbamic acid-3-(4-nitrophenyl)-allyl ester

Participants

Reaction Steps

A solution of 3-(4-nitrophenyl)-prop-2-en-1-ol (0.222 g, 1.24 mmol) and triethylamine (0.138 g, 0.19 mL, 1.37 mmol) in anhydrous CH2Cl2 (10 mL) was added to a solution of the isocyanate 7 prepared from the amine 5 (0.491 g, 1.24 mmol), triphosgene (0.132 g, 0.45 mmol) and triethylamine (0.17 g, 0.23 mL, 1.68 mmol) in anhydrous toluene (20 mL). The reaction was complete in 20 hours. The product was obtained (flash column chromatography 50% EtOAc/50% n-hexane) as a yellow oil which crystallised (0.432 g, 58%): νmax/cm−1 (film) (C=0, carbamate); [α]D25.3−65.0° (c=0.24, CHCl3), 1H NMR (CDCl3) δ 9.39 (bs, 1H), 7.89 ((s, 1H), 8.19 (d, J=8.8 Hz, 2H), 7.53 (d, J=9 Hz, 2H), 6.85 (s, 1H), 6.73 (d, J=15.9 Hz, 1H), 6.52 (dt, J=5.8, 15.9 Hz, 1H) 4.86 (m, 2H) 4.38 (m, 1H), 4.01 (m, 1H), 3.94 (s, 3H), 3.83 (s, 3H), 3.70 (m, 1H), 3.52 (m, 2H), 2.06 (m, 2H), 1.95 (m, 1H), 1.72 (m, 1H), 0.9 (s, 9H), 0.08 (s, 6H). IR (neat) 3340, 2930, 1729, 1597, 1519 cm−1. HRMS m/z calcd for C30H31N3O8SiNa 622.2561 (M+Na), found 622.2542.

Provenance & Evidence