Allylation of quinones bu allylic indium reagents

Article abstract of DOI:10.1016/0022-328X(91)83277-B

Allylation of a variety of quinones by allylic indium sesquihalides was studied.Reactions of unsubstituted p-benzoquinone with allylindium, prenylindium, and geranylindium reagents gave, after oxidation with silver oxide, the corresponding allylated quinones in good yields.These reactions appear to proceed via 1,2-addition of the allylic indium reagents at the γ-carbon followed by <3,3> sigmatropic rearrangement.Substituted quinones reacted with allylindium reagent giving excellent yields of allylquinols, whereas with prenylindium and geranylindium reagents, trisubstituted quinones gave diprenylcyclohexene-1,4-diones and 2,3-disubstituted quinones gave mixtures of prnylhydroquinones and diprenylcyclohexene-1,4-diones.In the prenylation of haloquinones, 1,2-addition, <3,3> sigmatropic rearrangement, and elimination of indium(III) halide occurred in sequence yielding prenylquinones. 2-Hydroxy- and 2-methoxy-1,4-naphthoquinones gave α-addition products with prenylindium and cinnamylindium reagents.