Synthesis of New 3-(-2-Alkenyl)-2-hydroxy-5-methoxy-p-benzoquinones via Claisen Rearrangement of Original 5-Methoxy-4-(2-propenyloxy)-o-benzoquinones

Article abstract of DOI:10.1055/s-1988-27547

The Claisen rearrangement is extended to compounds containing the benzoquinone moiety, obtained by regioselective nucleophilic substitution on 4-(p-methoxyphenoxy)-5-methoxy-o-benzoquinone (1).In the most general case, 5-methoxy-4-(2-propenyloxy)-o-benzoquinones 3 rearrange quantitatively into (E)-3-(2-alkenyl-2-hydroxy-5-methoxy-p-benzoquinones 4.Furfuryl or (2-thienyl)methyl ethers isomerize to 3-(2-methyl-3-furyl)- and 3-(2-methyl-3-thienyl)-2-hydroxy-5-methoxy-p-benzoquinones.This new synthetic method provides an efficient route to new hydroxybenzoquinones closelyrelated to natural compounds.Thus, dihydroardisiaquinone A is synthesized in 5 steps from p-methoxyphenol.