acetyl chloride in methanol 10 h; Inert atmosphere;

1.1: sodium hydride / tetrahydrofuran; mineral oil / 1 h / 0 °C 1.2: 2 h / 20 °C 2.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 2 h / 20 °C 3.1: sodium hydrogencarbonate; Dess-Martin periodane / dichloromethane / 1 h 4.1: 18-crown-6 ether; potassium hexamethylsilazane / tetrahydrofuran; toluene / 0.5 h / Cooling 4.2: 2 h / 20 °C / Cooling 5.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 24 h / 20 °C 6.1: di-isopropyl azodicarboxylate; triphenylphosphine / toluene / 1.5 h 7.1: water; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 1 h / 20 °C 8.1: Grubb's 2nd generation catalyst / dichloromethane / 6 h / 40 °C 9.1: hydrogenchloride; water / tetrahydrofuran / 20 h View Scheme

1.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 2 h / 20 °C 2.1: sodium hydrogencarbonate; Dess-Martin periodane / dichloromethane / 1 h 3.1: potassium hexamethylsilazane / tetrahydrofuran; toluene / 0.5 h / Cooling 3.2: 2 h / 20 °C / Cooling 4.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 24 h / 20 °C 5.1: di-isopropyl azodicarboxylate; triphenylphosphine / toluene / 1.5 h 6.1: water; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 1 h / 20 °C 7.1: Grubb's 2nd generation catalyst / dichloromethane / 6 h / 40 °C 8.1: hydrogenchloride; water / tetrahydrofuran / 20 h View Scheme

1.1: sodium hydrogencarbonate; Dess-Martin periodane / dichloromethane / 1 h 2.1: 18-crown-6 ether; potassium hexamethylsilazane / tetrahydrofuran; toluene / 0.5 h / Cooling 2.2: 2 h / 20 °C / Cooling 3.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 24 h / 20 °C 4.1: di-isopropyl azodicarboxylate; triphenylphosphine / toluene / 1.5 h 5.1: water; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 1 h / 20 °C 6.1: Grubb's 2nd generation catalyst / dichloromethane / 6 h / 40 °C 7.1: hydrogenchloride; water / tetrahydrofuran / 20 h View Scheme

1.1: 18-crown-6 ether; potassium hexamethylsilazane / tetrahydrofuran; toluene / 0.5 h / Cooling 1.2: 2 h / 20 °C / Cooling 2.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 24 h / 20 °C 3.1: di-isopropyl azodicarboxylate; triphenylphosphine / toluene / 1.5 h 4.1: water; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 1 h / 20 °C 5.1: Grubb's 2nd generation catalyst / dichloromethane / 6 h / 40 °C 6.1: hydrogenchloride; water / tetrahydrofuran / 20 h View Scheme

1.1: caesium carbonate; tetrakis(triphenylphosphine) palladium(0) / tetrahydrofuran; water / 2 h / 70 °C / |Inert atmosphere 2.1: sodium hydride / tetrahydrofuran; mineral oil / 0.5 h / 0 °C / |Inert atmosphere 2.2: 4 h / 0 °C / |Inert atmosphere 3.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 20 °C / |Inert atmosphere 4.1: Grubb's 2nd generation catalyst / dichloromethane / 4 h / 40 °C / |Inert atmosphere 5.1: acetyl chloride / methanol / 10 h / |Inert atmosphere View Scheme

1: sodium dihydrogenphosphate; sodium chlorite; 2-methyl-but-2-ene / water; tert-butyl alcohol 2: di-isopropyl azodicarboxylate; triphenylphosphine / toluene / 1.5 h 3: water; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 1 h / 20 °C 4: Grubb's 2nd generation catalyst / dichloromethane / 6 h / 40 °C 5: hydrogenchloride; water / tetrahydrofuran / 20 h View Scheme

1: tetrabutyl ammonium fluoride / tetrahydrofuran / 24 h / 20 °C 2: di-isopropyl azodicarboxylate; triphenylphosphine / toluene / 1.5 h 3: water; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 1 h / 20 °C 4: Grubb's 2nd generation catalyst / dichloromethane / 6 h / 40 °C 5: hydrogenchloride; water / tetrahydrofuran / 20 h View Scheme

1: di-isopropyl azodicarboxylate; triphenylphosphine / toluene / 1.5 h 2: water; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 1 h / 20 °C 3: Grubb's 2nd generation catalyst / dichloromethane / 6 h / 40 °C 4: hydrogenchloride; water / tetrahydrofuran / 20 h View Scheme

1: water; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 1 h / 20 °C 2: Grubb's 2nd generation catalyst / dichloromethane / 6 h / 40 °C 3: hydrogenchloride; water / tetrahydrofuran / 20 h View Scheme