1.1: sec-butyllithium; N,N,N',N'-pentamethyldiethylenetriamine / pentane; tetrahydrofuran / 6 h / -75 °C 1.2: 84 percent / 1,2-dibromo-1,1,2,2-tetrafluoroethane / pentane; tetrahydrofuran 2.1: 89 percent / tetrabutylammonium fluoride hydrate / tetrahydrofuran / 0.08 h / 25 °C View Scheme