Acyl migrations in Diels–Alder adducts of acyl-1,4-benzoquinones

Abstract

Treatment of several 4a-acyl-4a,5,8,8a-tetra-hydro-1,4-naph thoquinones with boiling acetic anhydride gives the 1,4-diacetoxy-2-acyl-5,8-dihydronaphthalenes, and the corresponding 1,4-dihydroxy-compounds are formed when acetic acid is used, but the latter are more readily obtained, via the Δ^8a,1enols, by treatment with pyridine or pyridine–methanol, these basic reagents cause deformylation of the 4a-formyl analogues, but transfer of the formly group to the oxygen at C-4 can be effected with imidazole.