Anodic　oxidation　of　catechols　has　been　investigated　in　the　presence　of　ketene　N,O-acetals　using　cyclic　voltammetry　and　constant　current　electrolysis　methods.　The　results　show　that　in　the　presence　of　ketene　N,O-acetals,　the　anodic　oxidation　of　4-methylcatechol　affords　alpha-arylated　products　in　satisfactory　yields.　Meanwhile,　indoles　can　be　synthesized　from　simple　3-substituted　catechols　or　catechol　itself　following　an　ECEC　mechanism.　In　addition,　either　alpha-arylation　or　indole　formation　could　be　the　dominant　pathway　by　simply　modifying　the　composition　of　the　electrolyte　solution.　(C)　2011　Elsevier　Ltd.　All　rights　reserved.