potassium phosphate; trans-N,N'-dimethylcyclohexane-1,2-diamine; copper(l) iodide in toluene T=120°C; 24 h; Inert atmosphere;

lithium diisopropyl amide in tetrahydrofuran; toluene T=0°C; 1 h; Inert atmosphereReflux;

1: With MgBr diethyl etherate; sec.-butyllithium in tetrahydrofuran; cyclohexane T=-75°C; 3 h; 2: With isopropyl alcohol in tetrahydrofuran; cyclohexane T=72°C; 3 h; Heating / reflux;

1: cyclopropyl acetylene With n-butyllithium in tetrahydrofuran; hexane T=0°C; 2: C13H13ClF3NO3 in tetrahydrofuran; hexane T=-70 - 65°C; 2.5 h; Heating / reflux;

1: With triethylamine in toluene T=0 - 10°C; Inert atmosphere; 2: With potassium carbonate in N,N-dimethyl-formamide T=20°C; 24 h;

in tetrahydrofuran Cyclization;

1.1: n-butyllithium / hexane; tetrahydrofuran / 1 h / -78 °C 1.2: 2.5 h / 0 °C 2.1: n-butyllithium / hexane; tetrahydrofuran / 1 h / -15 - 0 °C 2.2: 1.5 h / -45 - 0 °C 3.1: ethyl acetate / 5 h / 0 - 20 °C 3.2: 18.33 h / 0 - 20 °C 4.1: potassium phosphate / copper(l) iodide; trans-N,N'-dimethylcyclohexane-1,2-diamine / toluene / 24 h / 120 °C / Inert atmosphere View Scheme

1.1: n-butyllithium / hexane; tetrahydrofuran / 1 h / -15 - 0 °C 1.2: 1.5 h / -45 - 0 °C 2.1: ethyl acetate / 5 h / 0 - 20 °C 2.2: 18.33 h / 0 - 20 °C 3.1: potassium phosphate / copper(l) iodide; trans-N,N'-dimethylcyclohexane-1,2-diamine / toluene / 24 h / 120 °C / Inert atmosphere View Scheme

1.1: ethyl acetate / 5 h / 0 - 20 °C 1.2: 18.33 h / 0 - 20 °C 2.1: potassium phosphate / copper(l) iodide; trans-N,N'-dimethylcyclohexane-1,2-diamine / toluene / 24 h / 120 °C / Inert atmosphere View Scheme

1: n-BuLi / tetrahydrofuran 2: 3N aq. HCl 3: tetrahydrofuran 4: tetrahydrofuran View Scheme