1: 79 percent / NaBH4 / tetrahydrofuran; methanol / 0.5 h / Ambient temperature 2: 70 percent / p-toluenesulfonic acid / benzene / 0.5 h / Heating 3: 79 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / benzene / 0.17 h / Heating View Scheme

1: 79 percent / NaBH4 / tetrahydrofuran; methanol / 0.5 h / Ambient temperature 2: 70 percent / p-toluenesulfonic acid / benzene / 0.5 h / Heating View Scheme