1: 29 percent / 2N HCl / tetrahydrofuran / 0.5 h / Heating 2: t-BuOK / various solvent(s) / 1.) RT, 1 h, -60 deg C, 15 min, -30 deg C, 1 h View Scheme

1: 94 percent / t-BuOK / various solvent(s); tetrahydrofuran / 2.75 h / -10 - 25 °C 2: 29 percent / 2N HCl / tetrahydrofuran / 0.5 h / Heating 3: t-BuOK / various solvent(s) / 1.) RT, 1 h, -60 deg C, 15 min, -30 deg C, 1 h 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;