1: 41 percent / 10percent HCl, / H2O; tetrahydrofuran / Ambient temperature 2: diisopropylamine, n-butyllithium / THF, -78 deg C 3: dicyclohexylcarbodiimide, cuprous chloride / benzene / 26 h / Heating View Scheme

hydrogenchloride in tetrahydrofuran; water 4.5 h; Ambient temperature;