| Abstract
| - Intramolecular cycloadditions between cyclobutadiene and olefins can provide highly functionalizedcyclobutene-containing products. The outcome of the reaction depends on the nature of the tether connectingthe two reactive partners in the cycloaddition. Electronically unactivated olefins attached to cyclobutadienethrough a three-atom, heteroatom-containing tether yield successfully the desired cycloadducts, whereasthe corresponding substrates without a heteroatom linkage or with a longer tether are less prone to undergothe intramolecular cycloaddition. Calculations were used to help uncover some of the factors that influencethe course of the cycloaddition. Successful intramolecular reactions usually require either electronic activationof the dienophile, conformational restriction of the tether, or a slower oxidation protocol. In general, a facileintermolecular dimerization of cyclobutadiene is the major process that competes with the intramolecularcycloaddition.
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