tert-Butyl acrylate → 3-(5,7,8,9-Tetrahydro-6-oxa-1,9-diaza-benzocyclohepten-3-yl)-acrylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 3-Bromo-5,7,8,9-tetrahydro-6-oxa-1,9-diaza-benzocycloheptene (0.5 g, 2.2 mmol), tert-butyl acrylate (1.6 mL, 10.9 mmol) and (i-Pr)2EtN (1.1 mL, 6.5 mmol) in propionitrile/DMF (20 mL/5 mL) was de-oxygenated with Ar for 30 min. The mixture was treated with Pd(OAc)2 (49 mg, 0.22 mmol) and P(o-tol)3 (133 mg, 0.44 mmol) then heated to 100° C. for 16 h. The hot mixture was filtered through a pad of celite. The filtrate was diluted with H2O (100 mL) then extracted with dichloromethane (2×75 mL). The combined organic fractions were treated with brine (100 mL), dried over Na2SO4 and concentrated to give a yellow residue. This was subjected to flash chromatography on silica gel using 1.3% methanol:dichloromethane. The appropriate fractions were collected and concentrated to give a cream solid. Yield: 0.4 g (67%); 1H NMR (400 MHz, DMSO-d6) δ 8.19 (d, J=2.1 Hz, 1H), 7.87 (d, J=2.1 Hz, 1H), 7.44 (d, J=16.0 Hz, 1H), 6.87 (br s, 1H), 6.33 (d, J=16.0 Hz, 1H), 4.50 (s, 2H), 3.75-3.72 (m, 2H), 3.22-3.20 (m, 2H), 1.47 (s, 9H); ESI MS m/z 277 [C15H20N2O3+H]+

Provenance & Evidence