1: 100 percent / tetrahydrofuran; diethyl ether / 3 h / -78 °C 2: SO2, MeLi / tetrahydrofuran; diethyl ether / 12 h / -78 °C 3: 85 percent / 2percent Na(Hg), Na2HPO4 / tetrahydrofuran; methanol View Scheme

n-butyllithium in tetrahydrofuran; hexane 1.) -78 deg C, 3 h, 2.) -78 deg C, 3 h;

1: 91 percent / Et3N / CH2Cl2 / 1.) -78 deg C, 2 h, 2.) 0 deg C, 1 h 2: 67 percent / 2,6-lutidine / acetonitrile / 6 h / Heating 3: 100 percent / n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C, 3 h, 2.) -78 deg C, 3 h View Scheme

1: 67 percent / 2,6-lutidine / acetonitrile / 6 h / Heating 2: 100 percent / n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C, 3 h, 2.) -78 deg C, 3 h View Scheme