1: 52 percent / Cu(OAc)2*H2O / tetrahydrofuran; H2O / 0.67 h 2: 1) sodium hydride / 1) DMSO, room temperature, 15 min, 2) DMSO, 60 deg C, 3 h 3: p-toluenesulphonic acid / acetone / 5 h View Scheme

copper diacetate in tetrahydrofuran; water 0.666667 h;