392657-45-3Relevant academic research and scientific papers
Trimethylenemethane derivatives stabilized by conjugation II - Concerted or nonconcerted generation?
Roth, Wolfgang R.,Wildt, Holger,Schlemenat, Andreas
, p. 4081 - 4099 (2007/10/03)
The concerted formation of the orthogonal trimethylene-type diradicals 3, 6, and 12 has been demonstrated for the three homofulvenes 2, 4, and 7 and shown to proceed preferentially in a disrotatory manner. The same type of orthogonal diradicals are formed, but in a nonconcerted fashion, from the bicyclic methylenecyclopropanes 26, 30, 33, and 40, through the planar diradicals 28, 31, 35, and 50, respectively. The different reaction modes are viewed as being caused by the different coupling probabilities of the underlying vibrations. The orthogonal or planar geometries of the diradicals were derived from stereochemical and kinetic arguments. Additional thermodynamic characterization was achieved for three diradicals [3c, (E)-19, and 41] by oxygen-trapping experiments.
