silver trifluoroacetate in dichloromethane from -78 deg C to r.t.;

1: 88.5 percent / diethyl ether / 0.75 h / -78 °C 2: 1.) lithium diisopropylamide / 1.) tetrahydrofuran, hexane, 15 min 2.) 2 h at -78 deg C then 15 h at room temp., HMPA 3: lithium diisopropylamide / tetrahydrofuran; hexamethylphosphoric acid triamide / -78 °C 4: 90 percent / 30percent H2O2 / CH2Cl2 / 0.08 h / Ambient temperature 5: 83 percent / sodium methoxide / methanol / Ambient temperature View Scheme

in diethyl ether T=-78°C; 0.75 h;

methyllithium Yield given. Multistep reaction;

methyllithium Yield given. Multistep reaction;

2: 1.) n-BuLi / 1.) 1 h, -78 deg C, 2.) a) 0.5 h, -78 deg C, b) 2 h to 0 deg C 3: 71 percent / tetrahydrofuran / 16 h / Ambient temperature 4: 53 percent / 2.5 h / -50 - -40 °C View Scheme

1: 92 percent / DMDO / tetrahydrofuran; acetone / -78 °C 2: 74 percent / Pb(OAc)4, pyridine / benzene / 0 °C View Scheme