1: [4-chloro-3,6-difluoro-2-(methoxymethoxy)phenyl]trimethylsilane With 2,2,6,6-tetramethyl-piperidine; n-butyllithium in tetrahydrofuran; hexane T=-75°C; 2 h; 2: carbon dioxide in tetrahydrofuran; hexane 3: With hydrogenchloride pH=1;

1.1: 91 percent / N-ethyldiisopropylamine / CH2Cl2 / 2 h / 25 °C 2.1: BuLi / tetrahydrofuran; hexane / 2 h / -75 °C 2.2: 84 percent / tetrahydrofuran; hexane / 0.75 h / -75 °C 3.1: sec-BuLi; N,N,N',N'',N''-pentamethylethylenetriamine / tetrahydrofuran; cyclohexane / 2 h / -75 °C 3.2: 64 percent / 1,1,2-trichloro-1,2,2-trifluoroethane / tetrahydrofuran; cyclohexane 4.1: BuLi; 2,2,6,6-tetramethylpiperidine / tetrahydrofuran; hexane / 2 h / -75 °C 4.2: tetrahydrofuran; hexane 4.3: 65 percent / aq. HCl / pH 1 View Scheme

1.1: BuLi / tetrahydrofuran; hexane / 2 h / -75 °C 1.2: 84 percent / tetrahydrofuran; hexane / 0.75 h / -75 °C 2.1: sec-BuLi; N,N,N',N'',N''-pentamethylethylenetriamine / tetrahydrofuran; cyclohexane / 2 h / -75 °C 2.2: 64 percent / 1,1,2-trichloro-1,2,2-trifluoroethane / tetrahydrofuran; cyclohexane 3.1: BuLi; 2,2,6,6-tetramethylpiperidine / tetrahydrofuran; hexane / 2 h / -75 °C 3.2: tetrahydrofuran; hexane 3.3: 65 percent / aq. HCl / pH 1 View Scheme

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