dipyridinium dichromate in dichloromethane 18 h; Ambient temperature;

1: 91 percent / CuLi2Cl4 / tetrahydrofuran; diethyl ether / 0 °C 2: 80 percent / p-toluenesulfonic acid monohydrate / methanol 3: 60 percent / pyridinium dichromate / CH2Cl2 / 18 h / Ambient temperature View Scheme

1: 92 percent / p-toluenesulfonic acid monohydrate / tetrahydrofuran / 4 h / Ambient temperature 2: 91 percent / CuLi2Cl4 / tetrahydrofuran; diethyl ether / 0 °C 3: 80 percent / p-toluenesulfonic acid monohydrate / methanol 4: 60 percent / pyridinium dichromate / CH2Cl2 / 18 h / Ambient temperature View Scheme

1: 80 percent / p-toluenesulfonic acid monohydrate / methanol 2: 60 percent / pyridinium dichromate / CH2Cl2 / 18 h / Ambient temperature View Scheme