Rearrangements of cyclobutenones. Synthesis of N-methyl-7,8-dihydrobenzophenanthridine-9,12-diols and related compounds

Authors
Hergueta, AR Moore, HW
Citation
Ar. Hergueta et Hw. Moore, Rearrangements of cyclobutenones. Synthesis of N-methyl-7,8-dihydrobenzophenanthridine-9,12-diols and related compounds, J ORG CHEM, 64(16), 1999, pp. 5979-5983
Citations number
23
Categorie Soggetti
Chemistry & Analysis","Organic Chemistry/Polymer Science
Journal title
JOURNAL OF ORGANIC CHEMISTRY
ISSN journal
00223263 → ACNP
Volume
64
Issue
16
Year of publication
1999
Pages
5979 - 5983
Database
ISI
SICI code
0022-3263(19990806)64:16<5979:ROCSON>2.0.ZU;2-F
Abstract
A useful synthetic route to benzophenanthridines and annulated derivatives is reported. These arise from the thermolysis (refluxing chlorobenzene) of squaric acid-derived C(3-N-methyl-N-arylpropynyl)-cyclobutenones via a mech anism which involves an electrocyclic ring opening of the cyclobutenone to the corresponding enynylketenes. Subsequent ring closure to a diradical int ermediate followed by radical arylation gives the benzophenanthridines.