ChemInform Abstract: Transitions of Electron Demand in Pericyclic Reactions: Normal, Neutral, and Inverse Diels—Alder Reactions of Polyhalogenated Cyclopentadienes.

Abstract

The electronic modes of Diels-Alder reactions of a number of polyhalogenated cyclopentadienes with various aryl-substituted cyclic and open-chain dienophiles are investigated. For example, the cycloaddition of the cyclopentadiene (Ia) to styrene (IIa) is found to proceed with normal electron demand, whereas the reactions of (Ib) with the dienophiles (II) proceed with neutral electron demand, and the reactions of (Ic) with (II) proceed with inverse electron demand. The neutral cycloaddition can be regarded as a transition between normal and inverse Diels-Alder reaction. -(EIBLER, E.; HOECHT, P.; PRANTL, B.; ROSSMAIER, H.; SCHUHBAUER, H. M.; WIEST, H.; SAUER, J.; Liebigs Ann.