1: 100 percent / pyridinium toluene-p-sulphonate / CH2Cl2 / 4 h / Ambient temperature 2: 90 percent / tetrabutylammonium fluoride / tetrahydrofuran / 5.5 h / 0 °C 3: 93 percent / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 2 h / Ambient temperature 4: 99 percent / H2O, AcOH / tetrahydrofuran / 24 h / Ambient temperature View Scheme

1: 79 percent / toluene-p-sulphonic acid / CH2Cl2 / 3 h / 0 °C 2: 97 percent / tetrabutylammonium fluoride / tetrahydrofuran / 2.5 h / 0 °C 3: 100 percent / Jones reagent / acetone / 3.5 h / -20 °C 4: 89 percent / 1,5-diazabicyclo<5.4.0>undec-5-ene / benzene / 18 h / Ambient temperature 5: 99 percent / H2O, AcOH / tetrahydrofuran / 24 h / Ambient temperature View Scheme

1: 93 percent / lithium tri-s-butylborohydride / tetrahydrofuran / 0.5 h / -78 °C 2: 100 percent / pyridinium toluene-p-sulphonate / CH2Cl2 / 4 h / Ambient temperature 3: 90 percent / tetrabutylammonium fluoride / tetrahydrofuran / 5.5 h / 0 °C 4: 93 percent / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 2 h / Ambient temperature 5: 99 percent / H2O, AcOH / tetrahydrofuran / 24 h / Ambient temperature View Scheme

1: 87 percent / lithium tri-s-butylborohydride / tetrahydrofuran / 3 h / -78 °C 2: 79 percent / toluene-p-sulphonic acid / CH2Cl2 / 3 h / 0 °C 3: 97 percent / tetrabutylammonium fluoride / tetrahydrofuran / 2.5 h / 0 °C 4: 100 percent / Jones reagent / acetone / 3.5 h / -20 °C 5: 89 percent / 1,5-diazabicyclo<5.4.0>undec-5-ene / benzene / 18 h / Ambient temperature 6: 99 percent / H2O, AcOH / tetrahydrofuran / 24 h / Ambient temperature View Scheme

(i) MeLi, THF, (ii) aq. H2O2, KOCl, EtOH; Multistep reaction;