In Search of 1,4-Diazabutatrienes, the Elusive Isocyanide Homodimers: The Superchameleonic F–NC

Abstract

Figure 1. (a) Resonant forms of isocyanides 1 and (b) homodimerization of isocyanides 1 to afford 1,4-diazabutatrienes 2. Note pubs.acs.org/joc

Violations to the principle of least motion: the shortest path is not always the fastest

“…Recently, we published a theoretical study dealing with the homodimerization of isocyanides 47 towards 1,4-diazabutatrienes 49 (Scheme 11). 81–83 As in the dimerization of carbenes we observed that the habitually chameleonic 84 isocyanides follow a non-least-motion pathway along the reaction coordinate via the transition state 48 . Although in most of the cases both monomers behave equally along the non-least-motion reaction coordinate, in a few cases the independent monomers differ each other not only at the transition state structure but also at the early stages of the reaction, as is the case of the dimerization of F–NC, MeO–NC and SMe–NC.…”