lithium diisopropyl amide in tetrahydrofuran T=-65°C; 0.5 h;

1: With potassium hydride in tetrahydrofuran 0.666667 h; 2: With 1,2,2-trichloro-1,1,2-trichloro-ethane in tetrahydrofuran T=20°C; 3 h;

1.1: 96 percent / 3-chloroperoxybenzoic acid / CH2Cl2 / -15 °C 2.1: LDA; HMPA / tetrahydrofuran / 0.5 h / 0 °C 2.2: 78 percent / tetrahydrofuran / 0.5 h / 0 °C 3.1: KH / tetrahydrofuran / 0.67 h 3.2: 77 percent / C2Cl6 / tetrahydrofuran / 3 h / 20 °C View Scheme

1.1: LDA; HMPA / tetrahydrofuran / 0.5 h / 0 °C 1.2: 78 percent / tetrahydrofuran / 0.5 h / 0 °C 2.1: KH / tetrahydrofuran / 0.67 h 2.2: 77 percent / C2Cl6 / tetrahydrofuran / 3 h / 20 °C View Scheme

1.1: 89 percent / ethanol 2.1: 96 percent / 3-chloroperoxybenzoic acid / CH2Cl2 / -15 °C 3.1: LDA; HMPA / tetrahydrofuran / 0.5 h / 0 °C 3.2: 78 percent / tetrahydrofuran / 0.5 h / 0 °C 4.1: KH / tetrahydrofuran / 0.67 h 4.2: 77 percent / C2Cl6 / tetrahydrofuran / 3 h / 20 °C View Scheme

1: With potassium hydride in tetrahydrofuran T=0°C; 0.5 h; 2: With tert.-butyl lithium in tetrahydrofuran T=-78°C; 0.333333 h; 3: With sodium hydroxide in tetrahydrofuran T=-78 - 0°C; 0.333333 h;

Yield given. Multistep reaction;

ethylmagnesium bromide in tetrahydrofuran T=-70 - -40°C; 2 h;