1: 84 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) / CH2Cl2; H2O / 2 h 2: 1) Et3N, POCl3, 2) Et3N / 1) THF, a) 0 deg C, 1 h, b) room temp., 3 h, 2) THF, a) 0 deg C, 4 h, b) room temp., 8 h View Scheme