1: 95 percent / n-Bu4NF / tetrahydrofuran; dimethylsulfoxide / 0.25 h / 80 °C 3: 1) DIBAL, 2) NaF / 1) hexane, ether, 1h, 2) hexane, ether, dichloromethane 4: 92 percent / n-Bu4NF / tetrahydrofuran; dimethylsulfoxide / 30 h / 80 °C View Scheme

tetrabutyl ammonium fluoride in tetrahydrofuran; dimethyl sulfoxide T=80°C; 0.25 h;