1: 2.) hydrochloric acid / !:) ethyl ether, THF, reflux, 2.5 h, 2.) reflux, 3 h 2: 69 percent / ethanol / 2 h / Heating 3: 21 percent / tert-butyllithium / pentane; tetrahydrofuran / 1.) -78 deg C, 24 h, 2.) room temperature 4: 85 percent / m-chloroperbenzoic acid / CHCl3 / 24 h / 0 °C 5: 93 percent / boron trifluoride etherate / diethyl ether / 3 h / Ambient temperature View Scheme

1: 1.) cuprous iodide / 1.) ethyl ether, 2.) 25 deg C, 30 h 2: 80 percent / 456 °C / 0.1 Torr View Scheme

1: 2.) hydrochloric acid / !:) ethyl ether, THF, reflux, 2.5 h, 2.) reflux, 3 h 2: 69 percent / ethanol / 2 h / Heating 3: 21 percent / tert-butyllithium / pentane; tetrahydrofuran / 1.) -78 deg C, 24 h, 2.) room temperature 4: 44 percent / 550 °C / 0.1 Torr View Scheme