Triethyl phosphite → 2-(2-Cyclopentylethyl)-5-Phenyloxazole

Participants

Reaction Steps

To a stirred solution of 2-azido-1-phenylvinyl 3-cyclopentylpropionate from Step A (4.0 g, 14 mmol) in dry cyclohexane (10 mL) was added triethyl phosphite (12 g, 74 mmol) dropwise. After stirring at room temperature for 1 h, the mixture was heated at 90° C. in an oil bath under nitrogen for 6 h. The mixture was cooled and chromatographed on a silica gel column (eluent: 1:5 ethyl acetate:hexanes) to give 1.57 g (46.6%) of the title compound as a white solid: 1H NMR (400 MHz, CDCl3) δ7.59 (dt, 2H, J=2.0,8.2 Hz), 7.38 (dr, 2H, J=1.4, 8.0 Hz), 7.29 (tt, 1H, J=2.0, 8.0 Hz), 7.19 (s, 1H), 2.82 (t, 2H, 7.5 Hz), 1.89-1.75 (m, 5H), 1.61-1.47 (m, 4H), 1.11 (m, 2H).

Provenance & Evidence