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

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: diethyl ether / 1 h 6: 81 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: diethyl ether / 1 h View Scheme