Cyclohexenone derivatives of the formula (I) where R1 is alkyl, alkenyl, alkynyl, haloalkyl or haloalkenyl, alkoxyalkyl, unsubstituted or substituted cycloalkylmethyl, unsubstituted or substituted benzyl, or is a 5-membered heterocyclic ring which is bonded to the oxygen via a methylene unit, R2 is alkyl, R3 is hydrogen, alkylcarbonyl, alkenylcarbonyl, unsubstituted or substituted benzoyl, trialkylsilyl, alkyl- or arylsulfonyl, dialkylphosphono or -thiophosphono, or an organic or inorganic cation, R4 is unsubstituted or substituted alkyl, alkenyl or alkynyl, or unsubstituted or substituted cycloalkyl, and Y is hydrogen, methoxycarbonyl, cyano, alkyl or halogen, and herbicides containing these compounds.