How hydrides misled chemists

The folly of protobranching: turning repulsive interactions into attractive ones and rewriting the strain/stabilization energies of organic chemistry

Strain/stabilization energies: Recently it has been argued that the accepted strain/stabilization energies of fundamental species are incorrect because they ignore the effects of protobranching. Here it is shown that the basic premise of the protobranching mechanism is unlikely and that conventional strain/stabilization energies are more chemically important than those from the protobranching approach.

EPR data do not indicate that hyperconjugation stabilizes alkyl radicals

Ingold and DiLabio recently proposed that a correlation between C-H bond dissociation energies (BDE's) and spin delocalization terms calculated from EPR spectra was evidence that hyperconjugation plays an important role in stabilizing alkyl radicals. This correlation cannot be extended to C-C BDE's and the nature of the deviation is inconsistent with modern data on the 1,3 carbon-carbon interaction energies in alkanes. This result suggests that hyperconjugation is not a key factor in determining BDE's.