1.1: sec-BuLi; N,N,N',N'',N''-pentamethylethylenetriamine / tetrahydrofuran; cyclohexane / 2 h / -75 °C 1.2: 64 percent / 1,1,2-trichloro-1,2,2-trifluoroethane / tetrahydrofuran; cyclohexane 2.1: BuLi; 2,2,6,6-tetramethylpiperidine / tetrahydrofuran; hexane / 2 h / -75 °C 2.2: tetrahydrofuran; hexane 2.3: 65 percent / aq. HCl / pH 1 View Scheme