in tetrahydrofuran; dimethyl sulfoxide T=25°C; Corey - Chaykovsky reaction; 5 h; Inert atmosphere;

potassium carbonate in acetonitrile T=20°C; 48 h;

1: 80 percent / benzene / 15 h / Ambient temperature 2: 1) Ti(Oi-Pr)4, diethyl L-(+)-tartrate, tert-butyl hydroperoxide, 4 Angstroem molecular sieves / 1) CH2Cl2, -20 deg C, 20 h, 2) CH2Cl2, hexane, room temperature, 16 h 3: NaIO4 / tetrahydrofuran; H2O / 0.17 h / Ambient temperature 4: 4.34 g / CBr4, PPh3 / CH2Cl2 / 0.33 h / 0 °C 5: 87 percent / n-BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C View Scheme

1: tetrahydrofuran / 0.58 h / -78 °C / |Inert atmosphere 2: sodium hydrogencarbonate; Dess-Martin periodane / dichloromethane / 1.67 h / 20 °C / |Inert atmosphere View Scheme