1.1: n-BuLi / 1,2-dimethoxy-ethane; hexane / 0.17 h / -78 °C 1.2: 45 percent / 1,2-dimethoxy-ethane; hexane / 1 h / -78 °C 2.1: 66 percent / Na-Hg; Na2HPO4 / methanol / 2.5 h / 20 °C 3.1: 100 percent / Jones reagent / acetone / 0.5 h / 20 °C 4.1: 100 percent / trifluoroacetic acid / CH2Cl2 / 1.5 h / 20 °C 5.1: 91 percent / NaBH3CN / acetonitrile / 0.5 h / 20 °C View Scheme

Multistep reaction;