Construction of aryl-substituted triquinanes through the interrupted Nazarov reactiont

摘要

The first examples of intermolecular trapping of Nazarov cyclopentenyl cation intermediates by simple arenes to furnish α-arylcyclopentanones are described.rnThe Nazarov cyclization is a well established method for construction of substituted cyclopentanoid ring systems. Recently, we have shown that the electrophilic 2-oxidocyclo-pentenyl cation intermediate is subject to capture by a variety of pendent nucleophilic traps. We have been especially interested in trapping by arenes, as this process furnishes a-arylcyclopentanones from simple reactants. The intramolecular version of the reaction is effective, producing complex fused or bridged tricyclic systems from either dienone or dichlorocyclopropane precursors containing pendent arene traps. However, the corresponding bimolecular process could not be observed with dienone substrates that had been successfully captured intermolecularly by a variety of other traps.