A new synthetic route to ubiquinones

Article abstract of DOI:10.1002/hlca.19900730404

Ubiquinones 11 have been prepared employing a new strategy: as key step, the Diels-Alder reaction of 1,1,2-trichloroethene 3 with 2,5-bis[(trimethylsilyl)oxy]-3- methylfuran (2) has been used for the construction of the quinone part. After methanolysis of the [4 + 2] adducts 4a/4b, further reaction with cyclopentadiene and substitution of the Cl-atoms by MeO groups, the intermediate 7 is obtained. Diketone 7 can easily be alkylated with the desired polyprenyl side chain 9 (X = Br) using a strong base to yield, after a retro-Diels-Alder reaction, the corresponding ubiquinones 11 in high yields.