A number of polyalkylaromatic hydrocarbons can be synthesized by a novel method starting with the non-aromatic, commercially available isophorone (3,5,5-trimethyl-2-cyclohexene-l-one). The method appears to be general for 1,3-dimethyl-5-alkylbenzenes and with a simple modification can also be used for 1,3-dimethylbenzene (m-xylene); it is adaptable to the enlarged laboratory scale2 and gives products which are amenable to a high degree of purification.This method involves the reaction of isophorone with an alkyl Grignard reagent to produce a 1,3,5,5-tetra-alkylcyclohexenol, dehydration of the formed carbinol, and "demethanation"3 or aromatization of the resulting trimethyl-