Abstract: | Abstract A convenient and efficient synthetic route to Coenzyme Q1 (6) starting from 3,4,5‐trimethoxytoluene (1) is described. The key features of this synthesis include the Diels–Alder reaction of 2,3‐dimethoxy‐l,4‐benzoquinone (3) with cyclopentadiene and the introduction of a C5 side chain to 4,5‐dimethoxy‐2‐methyltricyclo[6.2.1.02,7]undeca‐4,9‐diene‐3,6‐dione (4) under mild conditions, (6) was obtained in overall 60% yield. |