A solution of the oxazolidinone (0.5 mmol) in toluene (20 ml) was heated to 200 °C in a sealed Carius tube (volume 50 ml) for 12 h. Evaporation of the solvent under reduced pressure followed by flash column chromatography on silica gel afforded the separated diastereoisomeric products.
Data for (2R,3S,4'S)-3'-(2,3-dihydro-2-phenylfuran-3-oyl)-4'-phenyloxazolidin-2'-one
mp. 142-143.5 °C. Rf = 0.2 (20% diethyl ether/light petroleum ). [a]D21 = +87 (c = 2.9, CHCl3). delta-H (400 MHz, CDCl3) 3.71 (1H, apparent t, OCHHCHPh, J=8.6), 3.98 (1H, dd, J=8.6, 2.6), 4.47 (1H, dd, J=8.6, 2.5), 4.97 (1H, apparent t, CH=CHO, J= 2.5Hz), 5.34 (1H, apparent dt, J= 11.6, 2.2Hz), 5.85 (1H, d, OCHPh, J= 11.6Hz), 6.68 (1H, apparent t, CH=CHO, J= 2.5Hz), 7.10-7.18 (2H, m, Ph), 7.22-7.46 (8H, m, Ph). delta-C (100 MHz, CDCl3) 52.87, 57.59, 69.89, 84.14, 98.32, 125.85, 127.22, 128.14, 128.61, 128.64, 129.01, 137.51, 138.77, 148.49, 153.35, 170.84. vmax 3054, 2918, 1777 (C=O), 1703 (C=O), 1631, 1494, 1456, 1381, 1347, 1239, 1195, 1045, 701 cm-1. [m/z] (EI): 77, 91, 104, 115, 145, 172, 335 (M)+; (CI) 164, 181, 336 (M+H)+, 353 (M+NH4)+. C20H17NO4 requires [(M+H)+] = 336.1236. Found [(M+H)+] = 336.1236.
