1: 1.) t-BuOK; 2.) 2N HCl / 1.) t-butyl methyl ether, -10 deg C - RT, 165 min; 2.) THF, reflux, 30 min 2: 1.) t-BuOK; 2.) 2N HCl / 1.) t-butyl methyl ether, -10 deg C - RT, 165 min; 2.) THF, reflux, 30 min 3: 1.) t-BuOK; 2.) 2N HCl / 1.) t-butyl methyl ether, -10 deg C - RT, 165 min; 2.) THF, reflux, 30 min 4: 0.8 M n-BuLi / tetrahydrofuran; hexane / 1.17 h / -20 °C View Scheme

potassium tert-butylate in various solvent(s) 1.) RT, 1 h, -60 deg C, 15 min, -30 deg C, 1 h; Yield given;

in tert-butyl methyl ether; water; ethyl acetate; Petroleum ether