1: Li2CuCl4 / tetrahydrofuran / 4 h / -30 °C 2: TsOH / methanol / Heating 3: pyridine View Scheme

1: dilithium tetrachlorocuprate / tetrahydrofuran / -20 °C / 1.) -20 deg C; 2.) -10 deg C, 1 h 2: H3O(1+) 3: LiAlH4 / 1,2-dimethoxy-ethane / 80 °C 4: pyridine 5: dilithium tetrachlorocuprate / tetrahydrofuran / -20 °C View Scheme