| Abstract
| - Thermal rearrangements of 2-allenyl- and 2-alkynyl-3-(2-ethenylphenyl)-4,4-dimethoxycyclobutenones werestudied. At ambient temperature, the allenyl compoundsundergo an electrocyclic cascade to give bicyclo[4.2.0]octadienyl-fused cyclobutenones. These unusual tetracycliccyclobutenones were shown to be viable synthetic precursorsto benzo[a]anthracene-7,12-diones, compounds representingthe framework of the angucycline group of naturally occurring antibiotics. In contrast, the 2-alkynylcyclobutenones arestable at ambient temperature but undergo a facile rearrangement at 110 °C (toluene) to give the previouslyunknown naphthalene derivatives, 1,2-dihydro-2,2-dimethoxy-1-(3-alkenylidene)naphtho[2,1-b]furans.
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