1: With N-ethyl-N,N-diisopropylamine in dichloromethane T=20°C; 2.5 h; Inert atmosphere; 2: With trimethylsilyl trifluoromethanesulfonate in acetonitrile T=0 - 20°C;

titanium tetrachloride in dichloromethane T=0°C; 0.75 h;

1: 96 percent / diisopropylethylamine / CH2Cl2 / 2 h / 0 °C 2: 17 percent / TiCl4 / CH2Cl2 / 0.75 h / 0 °C View Scheme