1: 83 percent / tetrahydrofuran / 22 h / Heating 2: 4.5 M HCl / 7 h / Heating View Scheme

1: 83 percent / tetrahydrofuran / 22 h / Heating 2: 1.) 4.5 M HCl, 2.) aq. NaOH / 1.) reflux, 7 h, 2.) 100 deg C, 1 h 3: 100 percent / diethyl ether; tetrahydrofuran / 1.17 h / Heating 4: 100 percent / trifluoroacetic acid / CHCl3 / 3 h / Ambient temperature View Scheme

1: 83 percent / tetrahydrofuran / 22 h / Heating 2: 1.) 4.5 M HCl, 2.) aq. NaOH / 1.) reflux, 7 h, 2.) 100 deg C, 1 h 3: 100 percent / diethyl ether; tetrahydrofuran / 1.17 h / Heating 4: 100 percent / trifluoroacetic acid / CHCl3 / 3 h / Ambient temperature 5: 92 percent / H2 / PtO2 / ethyl acetate / 2 h / 760 Torr / Ambient temperature View Scheme