Novel cyclohexanone derivatives of general formula: ##STR1## (wherein R.sup.1 is a hydrocarbon group of 1 to 15 carbon atoms) and new cyclohexanone derivatives of general formula: ##STR2## (wherein R.sup.1 and R.sup.2 each is a hydrocarbon group of 1 to 15 carbon atoms) are produced by an electrooxidative coupling of 1,3-cyclohexanedione with a vinyl ether of general formula:CH.sub.2 .dbd.CH-O-R.sup.1(wherein R.sup.1 is as defined above) in the presence or absence of an alcohol of general formula:R.sup.2 OH(wherein R.sup.2 is as defined above). These new cyclohexanone derivatives can be easily converted to N-substituted or unsubstituted-4-oxo-4,5,6,7-tetrahydroindoles, which are of value as intermediates for the production of N-substituted or unsubstituted-4-hydroxyindoles and, thence, to pindolol and its analogs.