Send to

Choose Destination
J Am Chem Soc. 2017 Nov 22;139(46):16650-16656. doi: 10.1021/jacs.7b07988. Epub 2017 Nov 9.

Bimodal Evans-Polanyi Relationships in Dioxirane Oxidations of sp3 C-H: Non-perfect Synchronization in Generation of Delocalized Radical Intermediates.

Liu F1,2, Yang Z2, Yu Y2,3, Mei Y1,4, Houk KN2.

Author information

State Key Laboratory of Precision Spectroscopy, School of Physics and Materials Science, East China Normal University , Shanghai 200062, China.
Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.
Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry and Chemical Engineering, Beijing University of Technology , Beijing 100124, China.
NYU-ECNU Center for Computational Chemistry at NYU Shanghai , Shanghai 200062, China.


The selectivities in C-H oxidations of a variety of compounds by DMDO have been explored with density functional theory. There is a linear Evans-Polanyi-type correlation for saturated substrates. Activation energies correlate with reaction energies or, equivalently, BDEs (ΔHsat = 0.91*BDE - 67.8). Unsaturated compounds, such as alkenes, aromatics, and carbonyls, exhibit a different correlation for allylic and benzylic C-H bonds (ΔHunsat = 0.35*BDE - 13.1). Bernasconi's Principle of Non-Perfect Synchronization (NPS) is found to operate here. The origins of this phenomenon were analyzed by a Distortion/Interaction model. Computations indicate early transition states for H-abstractions from allylic and benzylic C-H bonds, but later transition states for the saturated. The reactivities are mainly modulated by the distortion energy and the degree of dissociation of the C-H bond. While the increase in barrier with higher BDE is not unexpected from the Evans-Polanyi relationship, two separate correlations, one for saturated compounds, and one for unsaturated leading to delocalized radicals, were unexpected.


Supplemental Content

Full text links

Icon for American Chemical Society
Loading ...
Support Center