triethylamine in 1,4-dioxane; water T=0°C;

tetra-n-butylammonium fluoride trihydrate in tetrahydrofuran T=20°C; 12 h;

1.1: dichloromethane / 20 h / 20 °C 2.1: 1H-imidazole / N,N-dimethyl-formamide / 67 h / 40 °C 3.1: N,N,N',N,-tetramethylethylenediamine; sec.-butyllithium / diethyl ether; hexane / 4 h / -80 - -20 °C 3.2: -80 - 20 °C 4.1: tetra-n-butylammonium fluoride trihydrate / tetrahydrofuran / 12 h / 20 °C View Scheme

1.1: dichloromethane / 20 h / 20 °C 2.1: 1H-imidazole / N,N-dimethyl-formamide / 67 h / 40 °C 3.1: N,N,N',N,-tetramethylethylenediamine; sec.-butyllithium / diethyl ether; hexane / 4 h / -80 - -20 °C 3.2: -80 - 20 °C 4.1: tetra-n-butylammonium fluoride trihydrate / tetrahydrofuran / 12 h / 20 °C View Scheme

1.1: N,N,N',N,-tetramethylethylenediamine; sec.-butyllithium / diethyl ether; hexane / 4 h / -80 - -20 °C 1.2: -80 - 20 °C 2.1: tetra-n-butylammonium fluoride trihydrate / tetrahydrofuran / 12 h / 20 °C View Scheme

1.1: 1H-imidazole / N,N-dimethyl-formamide / 67 h / 40 °C 2.1: N,N,N',N,-tetramethylethylenediamine; sec.-butyllithium / diethyl ether; hexane / 4 h / -80 - -20 °C 2.2: -80 - 20 °C 3.1: tetra-n-butylammonium fluoride trihydrate / tetrahydrofuran / 12 h / 20 °C View Scheme

1: diisopropylamine / tetrahydrofuran / 22 h / Reflux 2: tetra-n-butylammonium fluoride trihydrate / tetrahydrofuran / 12 h / 20 °C View Scheme

in dichloromethane T=20°C; 4 h;