Vinylindenes and Some Heteroanalogues in the Diels-Alder Reaction. IX. 3-Vinylbenzofuran and 1,4-Naphthoquinone

Abstract

3-Vinylbenzofuran and 1,4-naphthoquinone react to give r-5a,6,c-12a,c-12b-tetrahydroanthra-[1,2-b]benzofuran-5,13-quinone. This adduct undergoes ring opening to 2-(2-hydroxyphenyl)-anthraquinone with base and oxygen, but shows no rearrangement to anthra[2,3-b]benzofuran- 5,13-quinone.