1: With oxalyl dichloride; dimethyl sulfoxide in dichloromethane T=-78°C; 0.5 h; Inert atmosphere; 2: With triethylamine in dichloromethane T=-78 - 20°C; Inert atmosphere;

trichlorophosphate in N,N-dimethyl-formamide 6 h; Heating;

1: SOCl2 / pyridine 2: K2Cr2O7, aq. H2SO4 / benzene View Scheme

2: 97 percent / MgSO4 / diethyl ether / 24 h / Ambient temperature 3: 100 percent / KOtBu / tetrahydrofuran / 3 h / Heating; or 3 d at rt; also with KCN in CH3OH, reflux, 5 h 4: 95 percent / aq. oxalic acid / 48 h / Ambient temperature; or with 2N aq. HCl at rt during 2 d 5: 60 percent / 2N aq. HCl / 72 h / Heating View Scheme

1: 30 percent / dimethylsulfoxide / 2 h / 58 °C 2: 71 percent / chloroplatinic acid hexahydrate / ethanol / 1.25 h / 65 - 75 °C View Scheme