Benzoquinones and related compounds. Part 4. Thermolysis of the Diels–Alder adduct of 2-acetyl-5,6-dichloro-1,4-benzoquinone and cyclopentadiene: evidence for a partial retro-diene reaction
作者:Roy L. Beddoes、J. Malcolm Bruce、Harry Finch、Leslie M. J. Heelam、Ian D. Hunt、Owen S. Mills
DOI:10.1039/p19810002670
日期:——
cyclopentadiene yields, predominantly, the 1:1 Diels–Alder adduct (6) by endo-addition to the 2,3-double bond. Thermolysis of this adduct in benzene results in disproportionation to cyclopentadiene and the spiro-acetal (13); thermolysis in acetic acid also yields (13), but the major product is the dihydrobenzofuran (14), an isomer of the Diels–Alder adduct. Mechanisms for the formation of these products are