in dimethyl sulfoxide T=80 - 90°C; 41 h;

1: 1) pivaloyl chloride / 1) tetrahydrofuran, 5 deg C, 1 h, 2) a) room temperature, 1 h, b) reflux, 6 h 2: 84 percent / dimethylsulfoxide / 41 h / 80 - 90 °C View Scheme