1.1: 57 percent / pTsOH / tetrahydrofuran; H2O / 4 h / Heating 2.1: MsCl; Et3N / CH2Cl2 / 0.33 h / -10 °C 2.2: 82 percent / DBU / CH2Cl2 / 4 h / 20 °C 3.1: AgClO4 / Cp2ZrCl2 / CH2Cl2 / 4 h / 0 °C 3.2: 70 percent / aq. LiOH / tetrahydrofuran / 10 h / 20 °C 4.1: 88 percent / toluene; diethyl ether / 0.5 h / 20 °C 5.1: 60 percent / TiCl4 / CH2Cl2; diethyl ether / 0.25 h / -78 °C 6.1: PCC; 4A MS / CH2Cl2 / 2 h / 20 °C 6.2: 64 percent / piperidinium acetate / benzene / 2 h / Heating View Scheme