1: 1,3-difluoro-5-(methoxymethoxy)benzene With n-butyllithium in diethyl ether; hexane T=-75°C; 6 h; 2: carbon dioxide in diethyl ether; hexane 3: With hydrogenchloride pH=1;

1.1: BuLi; t-BuOK / tetrahydrofuran; hexane / 2 h / -75 °C 1.2: 78 percent / tetrahydrofuran; hexane / 0.75 h / -75 °C 2.1: sec-BuLi / tetrahydrofuran; cyclohexane / 2 h / -75 °C 2.2: tetrahydrofuran; cyclohexane 2.3: 89 percent / aq. HCl / pH 1 View Scheme

N-ethyl-N,N-diisopropylamine in dichloromethane T=25°C; 2 h;

potassium carbonate in acetone T=20°C;