New inter- and intramolecular carbo- and heterocyclizations of 4-methyl-4-trichloromethylcyclohexa-2,5-dien-1-one and its η4-rhodiumcyclopentadienyl complex under the action ofn-buthyllithium: formation of functionally substituted tricyclic spirofuran and bicyclo[2.2.1]heptadiene systemscomplex under the action ofn-buthyllithium: formation of functionally substituted tricyclic spirofuran and bicyclo[2.2.1]heptadiene systems

Autor: Pavel V. Petrovskii, D. V. Zverev, S. V. Sergeev, V. A. Nikanorov
Rok vydání: 1997
Předmět:
Zdroj: Russian Chemical Bulletin. 46:1454-1457
ISSN: 1573-9171
1066-5285
Popis: Treatment with BunLi in THF (−60–0°C) causes 4-methyl-4-trichloromethylcyclohexa-2,5-dien-1-one and itsexo-η4-coordinated (by a RhCp-group) π-diene metal complex to undergo reactions of two new types: intermolecular autocondensation-heterocyclization (affording 3,3-dichloro-3a,4′-dimethyl-4′-trichloromethyl-2,3,3a,6,7,8-hexahydrospiro-[benzofuran-2,1′-cyclohexa-2′, 5′-dien]-6-one; 24%) and intramolecular carbocyclization (yielding (η4-7,7-dichloro-1-hydroxy-4-methylbicyclo[2.2.1]hepta-2,5-diene)(η5-cyc;opentadienyl)rhodium: 77%). Both processes are assumed to involve the formation of an unusualgem-CCl2Li substitutedpara-semiquinoid intermediate, the conformation of the six-membered diene ring of which (planar or a boat-like) governs its subsequent intra- or intermolecular stereospecific carbonyl condensations.
Databáze: OpenAIRE
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