tert-Butyl acrylate → (E)-7-(2-tert-Butoxycarbonyl-vinyl)-2-oxo-1,2,3,5-tetrahydro-pyrido[2,3-e][1,4]diazepine-4-carboxylic acid benzyl ester

Participants

Reaction Steps

A suspension of 7-bromo-2-oxo-1,2,3,5-tetrahydro-pyrido[2,3-e][1,4]diazepine-4-carboxylic acid benzyl ester (0.52 g, 1.4 mmol) in propionitrile (10 mL) and DMF (3 mL) was de-oxygenated with Ar for 20 min. The mixture was treated with tert-butyl acrylate (0.83 mL, 10 mmol) and (i-Pr)2EtN (0.50 mL, 2.9 mmol) and was de-oxygenated with Ar for 10 min. Pd(OAc)2 (34 mg, 0.15 mmol) and P(o-tol)3 (84 mg, 0.27 mmol) were added simultaneously, and the mixture was de-oxygenated a third time for 5 min. The mixture was heated to reflux overnight, then allowed to cool. The resulting precipitate was isolated by filtration, washed with EtOAc and dissolved in CH2Cl2. The solution was filtered through Celite and the solvent was removed in vacuo to give the title compound (0.31 g, 53%) as an off-white solid: 1H NMR (300 MHz, CDCl3) δ 8.49-8.57 (m, 1H), 8.30 (s, 1H), 7.43-7.73 (m, 2H), 7.33 (s, 4H), 7.17-7.18 (m, 1H), 6.21-6.40 (m, 1H), 5.05-5.11 (m, 2H), 4.46-4.68 (m, 4H), 1.54-1.57 (m, 9H); MS (ESI) m/e 424 (M+H)+.

Provenance & Evidence