1.1: 89 percent / aq. H2SO4 / acetone / 2.5 h / ultrasonication 2.1: 99 percent / PDC / CH2Cl2 / 6 h 3.1: nBuLi / hexane; tetrahydrofuran / 5 h / -78 - 0 °C 3.2: 73 percent / tetrahydrofuran; hexane / 5 h / 20 °C 4.1: nBu4NF*3H2O / tetrahydrofuran / 23 h 5.1: 20 mg / AG 50W-X4 resin / methanol / 24 h View Scheme

1.1: 89 percent / aq. H2SO4 / acetone / 2.5 h / ultrasonication 2.1: 99 percent / PDC / CH2Cl2 / 6 h 3.1: nBuLi / hexane; tetrahydrofuran / 5 h / -78 - 0 °C 3.2: 92 percent / tetrahydrofuran; hexane / 5 h / 20 °C 4.1: nBu4NF*3H2O / tetrahydrofuran / 22 h 5.1: AG 50W-X4 resin / methanol / 22 h View Scheme