The Baeyer strain is strongly affected by the nucleus-electron attraction-a comment on the Letter of G. Hohlneicher and L. Packschies [Tetrahedron Lett. 2007, 48, 6429-6433]

The origin of the angular strain is studied in deformed methane and cyclohexane selected as the model systems par excellence. It is shown that the electron correlation contribution to the angular strain is negligible. Analysis of the Hartree-Fock energies provides a convincing evidence that the angular strain is a consequence of the unfavourable nucleus-electron attraction occuring due to bond bending. This should take place in other angularly distorted molecules as a rule. However, other effects might be even more important sometimes. In these cases the Vne term can serve as a useful diagnostic tool.

Graphical abstractDownload full-size image