1: 1.) butyllithium, HMPA / 1.) THF, hexane, from -25 to -20 deg C, 20 min, 2.) THF, hexane, -20 deg C, 2 h 2: Na-Hg, Na2HPO4, MeOH / tetrahydrofuran / 3 h / Ambient temperature 3: 30 percent / H3PMo12O40*5H2O / dioxane; H2O / 3 h / 30 °C View Scheme

1: 56 percent / 2M BuLi / 1.) THF-hexane, -70 deg C; 2.) THF-hexane-HMPT, 0 deg C 2: 40 percent / Na / methanol / 0 °C 3: p-TsOH*H2O / dioxane; H2O / 4 h / 80 °C View Scheme

toluene-4-sulfonic acid in benzene 0.5 h; Ambient temperature;

1: 12.8 percent / tetrahydrofuran; diethyl ether / 1.) 5 deg C, 90 min; 2.) 3 deg C, 3 h 2: 76 percent / p-TsOH / benzene / 0.5 h / Ambient temperature View Scheme