Reaction Steps
CuCN (120 mg, 1.3 mmol) was added to a stirred solution of 5a (150 mg, 0.30 mmol) in NMP (1.0 mL) at rt. The reaction mixture was heated at 220° C. for 20 min using microwave irradiation and the solvent was then removed by lyophilisation from deionised water. The residue was thoroughly extracted with CH2Cl2, dried and concentrated. Purification by silica gel chromatography (heptane:EtOAc, 1:1) gave 6a as a white foam (110 mg, 82%):[α]D−83 (c 1.0, CHCl3); IR λ 3012, 2956, 2217, 1751, 1654, 1486, 1442, 1369 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.79 (d, J=7.8, 1H), 7.70 (d, J=8.1, 1H), 7.62 (d, J=8.2, 1H), 7.47-7.29 (m, 3H), 7.19-6.92 (m, 5H), 6.87 (d, J=7.3, 1H), 5.79 (dd, J=8.9, 2.3, 1H), 4.41-4.27 (m, 2H), 3.89 (s, 3H), 3.75 (dd, J=11.9, 8.9, 1H), 3.52 (dd, J=11.9, 2.3, 1H); 13C NMR (100 MHz, CDCl3) δ 167.6, 160.7, 158.7, 155.2, 134.4, 133.6, 132.4, 131.4, 129.7, 129.2, 128.8 (broad and splitted), 128.6, 127.6, 126.1, 125.7, 125.3, 125.2, 122.7, 117.1, 115.2, 101.3, 64.4, 53.7, 35.3, 31.8; HRMS (EI+) calcd for C27H20N2O3S 452.1195, obsd 452.1192.
