toluene-4-sulfonic acid in ethyl acetate; benzene

lead(IV) acetate

1.1: Et3N / dimethylformamide / 0.5 h / 0 °C 1.2: 79 percent / dimethylformamide / 0 - 20 °C 2.1: periodic acid / tetrahydrofuran / 1.5 h / 20 °C 2.2: 63 percent / water / tetrahydrofuran / 72 h / 4 °C 3.1: 1.21 g / toluene / Heating View Scheme

in toluene Heating;