54789-38-7Relevant academic research and scientific papers
Forbidden reactions, II. - The disrotatory cyclobutene ringopening
Roth, Wolfgang R.,Rekowski, Volker,Boerner, Sabine,Quast, Michael
, p. 409 - 430 (2007/10/03)
The energy profiles for the con- and disrotatory opening of benzocyclobutene, methylenecyclobutene, and cyclobutene derivatives were established by NO and oxygen trapping. The enthalpy for the transition states for the "forbidden" reactions proofed to be identical with the heat of formation of the orthogonal diradicals derived by geometrical isomerization of the dienes formed in these reactions. These diradicals describe very well the activation barriers observed for the disrotatory opening of bicyclic cyclobutenes ([3.2.0] and [2.2.0] systems), but not for bicyclo[2.1.0]pent-2-ene, indicating here a truly forbidden reaction. VCH Verlagsgesellschaft mbH, 1996.
