1: 100 percent / triethylorthoformate / p-toluenesulfonic acid / 25 h / Ambient temperature 2: tetrahydrofuran / 5 h / -78 - 25 °C 3: K2CO3, 18-crown-6 / tetrahydrofuran / 21 h / 40 °C 4: 95 percent / hexane / 68 h / 25 °C / Irradiation 5: NaH / diethyl ether / 0 - 25 °C View Scheme

1: 82 percent / AcOH, LiCl / hexamethylphosphoric acid triamide / 17.5 h / 110 °C 2: 100 percent / triethylorthoformate / p-toluenesulfonic acid / 25 h / Ambient temperature 3: tetrahydrofuran / 5 h / -78 - 25 °C 4: K2CO3, 18-crown-6 / tetrahydrofuran / 21 h / 40 °C 5: 95 percent / hexane / 68 h / 25 °C / Irradiation 6: NaH / diethyl ether / 0 - 25 °C View Scheme

1: 1.) methanol, reflux, 13 h; 2.) toluene , reflux, 21 h. 2: 82 percent / AcOH, LiCl / hexamethylphosphoric acid triamide / 17.5 h / 110 °C 3: 100 percent / triethylorthoformate / p-toluenesulfonic acid / 25 h / Ambient temperature 4: tetrahydrofuran / 5 h / -78 - 25 °C 5: K2CO3, 18-crown-6 / tetrahydrofuran / 21 h / 40 °C 6: 95 percent / hexane / 68 h / 25 °C / Irradiation 7: NaH / diethyl ether / 0 - 25 °C View Scheme

sodium hydride in diethyl ether T=0 - 25°C;

1: 95 percent / hexane / 68 h / 25 °C / Irradiation 2: NaH / diethyl ether / 0 - 25 °C View Scheme

1: tetrahydrofuran / 5 h / -78 - 25 °C 2: K2CO3, 18-crown-6 / tetrahydrofuran / 21 h / 40 °C 3: 95 percent / hexane / 68 h / 25 °C / Irradiation 4: NaH / diethyl ether / 0 - 25 °C View Scheme

1: K2CO3, 18-crown-6 / tetrahydrofuran / 21 h / 40 °C 2: 95 percent / hexane / 68 h / 25 °C / Irradiation 3: NaH / diethyl ether / 0 - 25 °C View Scheme