Study on the reactivity of oxabicyclic alkenes in ruthenium-catalyzed [2+2] cycloadditions.
The ruthenium-catalyzed [2+2] cycloadditions of various bicyclic alkenes with an alkyne have been investigated. The presence of the oxygen in the bridgehead of the bicyclic alkene significantly enhanced the rate of the ruthenium-catalyzed [2+2] cycloadditions. The presence of a C1-substituent on the oxanorbornadiene decreased the rate of the cycloaddition and electron-withdrawing C1-substituents were found to be more reactive than electron-donating C1-substituents in the Ru-catalyzed [2+2] cycloaddition. The nature of the substituent on the benzene ring of oxabenzonorbornadienes showed little effect on the rate of the cycloaddition.
Burton
Ryan R
RR
Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry, University of Guelph, Guelph, Ontario, Canada.
Tam
William
W