The carbonation is the most electron-withdrawing carbon based substituent that one can generate. Thus, our discovery that allyl cautions were extremely powerful dielophiles in the Diels-Alder reactions was complerely consistent with what theory would predict. Our early studies demonstrated that allyl cations added either intramolecularly or intermolecularly to dienes with the formation of 2pi + 4pi Diels-Alder adducts in high yields at temperatures as low as -78 degrees C. We plan to continue to study the details of this reaction and to attend our studies to a variety of other dienophiles. Studies will continue on: (a) the affect of substituents on the diene on the cycloaddition, (b) regiochsmistry of both the intramolacular and intermolecullar cycloadditions, and (c) cycloadditions under neutral condition. Studies new to this proposal will involve (a) the use of carbocations to activate allenas as dienophile, (b) the use of carbocations to activate nitriles as dienophiles, (c) the use of carbocations to activate carbonyls as dienophiles, and (d) the addition of electron-rich dienophiles to pentadienyl cations.
