1: DDQ / benzene / 18 h / Heating 2: 1.) BuLi / 1.) ether, -70 deg C 5 min, 2.) ether, -70 deg C- -55 deg C, 10 min, then to 0 deg C, 3 h View Scheme

1: DDQ / benzene / 18 h / Heating 2: 71 percent / O2 / tetrahydrofuran / 0.33 h / 20 °C / Irradiation; Rose Bengal, sens. View Scheme

1: DDQ / benzene / 18 h / Heating 2: 1.) BuLi / 1.) ether, -70 deg C 5 min, 2.) ether, -70 deg C- -55 deg C, 10 min, then to 0 deg C, 3 h 3: 70 percent / pyridine / Ambient temperature View Scheme

With  sodium tetrahydroborate in  methanol 3 h;  Ambient temperature;