practical synthesis of coenzyme Q10 has been developed. The route features an improved Friedel–Crafts allylation of tetramethoxytoluene with a para-chlorobenzenesulfonyl-substituted C5 allylic chloride at 40 °C. Replacement of the methyl ether protecting groups of the para-hydroquinone by methoxymethyl groups at Q1 stage proceeded efficiently, and allowed the facile final oxidation to coenzyme Q10 to