1: 51 percent / DDQ / benzene / 12 h / Heating 2: ethanol / 15 h / Ambient temperature 3: 52 percent / NaCNBH3, bromocresol green, HCl / dimethylformamide; tetrahydrothiophene 1,1-dioxide / 5 h / 110 °C 4: BBr3 / CH2Cl2 / 3 h / -78 - 0 °C 5: (NH4)2Ce(NO3)6 / acetonitrile; H2O View Scheme

1: 51 percent / DDQ / benzene / 12 h / Heating 2: ethanol / 15 h / Ambient temperature 3: 83 percent / n-BuLi / diethyl ether; hexane 4: NaH, ethanethiol / dimethylformamide / 10 h / 130 °C 5: (NH4)2Ce(NO3)6 / acetonitrile; H2O View Scheme