dihydrogen peroxide in dichloromethane T=0 - 20°C; 0.75 h;

1: α-methyl-γ-butyrolactone With lithium diisopropyl amide in tetrahydrofuran T=-78°C; 0.333333 h; 2: bis[4-(trimethylsilyl)phenyl]diselenide in tetrahydrofuran T=-78°C; 1 h;

1.1: Mg; I2 / tetrahydrofuran / 1.5 h / 20 °C 1.2: selenium / tetrahydrofuran / 3 h / 45 °C 1.3: 65 percent / NaBH4 / methanol / 1.5 h / 0 °C 2.1: LDA / tetrahydrofuran / 0.33 h / -78 °C 2.2: 85 percent Turnov. / tetrahydrofuran / 1 h / -78 °C View Scheme