1.1: 52 percent / tetrahydrofuran / 0.67 h / Heating 2.1: TiCl4 / CH2Cl2 / 0.25 h / -78 °C 2.2: 7.2 percent / CH2Cl2 / 5 h / -78 °C 3.1: 76 percent / Bu4NF / tetrahydrofuran / 0.33 h / 20 °C View Scheme

1: lithium aluminum hydride / diethyl ether; tetrahydrofuran / 2 h / -78 - 20 °C 2: Et3N, methanesulfonyl chloride / CH2Cl2 / 24 h / Ambient temperature 3: tetra-n-butylammonium fluoride / tetrahydrofuran; diethyl ether / 0.17 h / Ambient temperature View Scheme