oxalyl dichloride; dimethyl sulfoxide in dichloromethane T=-5°C; 0.25 h;

1: 80 percent / LiAlH4 / diethyl ether / 2.5 h / -100 °C 2: 49 percent / oxalyl chloride, DMSO / CH2Cl2 / 0.25 h / -5 °C View Scheme