hydrogenchloride in methanol 2 h; Heating;

1: 4 N aq. HCl / methanol; dioxane / 50 °C 2: K2CO3 / acetone / 15 h / 60 °C 3: NaOEt / ethanol / 20 h / 0 °C View Scheme

potassium hexamethylsilazane in tetrahydrofuran T=-65°C; other aldehydes; also with LiHMDS use; Product distribution;

lithium hexamethyldisilazane 1.) THF, from -60 deg C to -55 deg C, 45 min, 2.) a) from -65 deg C to 25 deg C, 3 h, b) 25 deg C, 24 h; Yield given. Multistep reaction;

1: 1.) ether, -10 deg C, 3 h, 2.) ether, THF, -10 deg C, 1 h 2: 67.1 percent / conc.sulphuric acid / aq. acetic acid / 26 h 3: 1.) BuLi / 1.) ether, hexane, 2.5 h, 2.) ether, hexane, 30 min View Scheme