1: K2CO3 / methanol / 1 h / 20 °C 2: 90 percent / Et3N / hexane / 24 h / 0 - 20 °C 3: tetrahydrofuran / 12 h / 0 - 20 °C 4: TBAF / tetrahydrofuran / 6 h View Scheme

1: K2CO3 / methanol / 1 h / 20 °C 2: 90 percent / Et3N / hexane / 24 h / 0 - 20 °C 3: tetrahydrofuran / 12 h / 0 - 20 °C 4: TBAF / tetrahydrofuran / 6 h 5: Et3N / CH2Cl2 / 0 - 20 °C 6: 18-crown-6 / CH2Cl2 / 6 h / Heating View Scheme

1.1: K2CO3 / methanol / 1 h / 20 °C 2.1: 90 percent / Et3N / hexane / 24 h / 0 - 20 °C 3.1: tetrahydrofuran / 12 h / 0 - 20 °C 4.1: TBAF / tetrahydrofuran / 6 h 5.1: Et3N / CH2Cl2 / 0 - 20 °C 6.1: 18-crown-6 / CH2Cl2 / 6 h / Heating 7.1: diethyl ether / -78 - 0 °C 7.2: aq. NH4Cl / diethyl ether / 0.17 h / 0 °C View Scheme