n-butyllithium; iodine; 1,1,1,3,3,3-hexamethyl-disilazane in tetrahydrofuran T=-78°C; 0.166667 h;

1: 81 percent / (COCl)2; DMSO; Et3N / CH2Cl2 2: 33 percent / HMDS; n-BuLi; I2 / tetrahydrofuran / 0.17 h / -78 °C View Scheme