Electrochemical reduction of exo-5-acetyl-endo-6-trichloromethylbicyclo[2.2.1]hept-2-ene (2) using a mercury cathode gave chemoselectively either the corresponding monochloromethyl or dichloromethyl derivatives in high yields by selecting supporting electrolyte. The reduction of 2 using a lead cathode gave 2-acetyl-3-methylbicyclo[2.2.1]hepta-2,5-diene and cis-1-(4-vinyl-2-cyclopentenyl)-2-propanone