Electron Transfer and Polar Reactions of Cyclizable Anion Radicals: Structural Consequences of Orbital Selection Rules and Chain‐Length Constraints

Transition states for electron transfer with strong bonding interactions are reported in the reactions of anion radicals 1 (n = 2,3). The heights of the activation barriers for the substitution and electron transfer pathways leading to 2 and 3, respectively, are a function of the length n of the methylene chain. This is predicted on the basis of orbital selection rules derived from valence bond configuration mixing analysis, and confirmed here by ab initio calculations. (Figure Presented.)