dimethylsulfide borane complex in tetrahydrofuran 3 h; Heating / reflux;

1: With oxalyl dichloride; dimethyl sulfoxide in dichloromethane T=-78°C; 0.25 h; 2: 2-chloro-3-methylbenzyl alcohol in dichloromethane 0.5 h; 3: With triethylamine in dichloromethane T=20°C; 1 h;