Dynamics-Driven Reaction Pathway in an Intramolecular Rearrangement
Salai Cheettu Ammal,1
Hiroshi Yamataka,1*
Misako Aida,2*
Michel Dupuis3*
A critical role is traditionally assigned to
transition states (TSs) and minimum energy pathways, or intrinsic
reaction coordinates (IRCs), in interpreting organic reactivity. Such
an interpretation, however, ignores vibrational and kinetic energy
effects of finite temperature. Recently it has been shown that
reactions do not necessarily follow the intermediates along the IRC. We
report here molecular dynamics (MD) simulations that show that dynamics effects may alter chemical reactions even more. In the heterolysis rearrangement of protonated pinacolyl alcohol
Me3C-CHMe-OH2+ (Me, methyl), the MD
pathway involves a stepwise route with C-O bond cleavage followed by
methyl group migration, whereas the IRC pathway suggests a concerted
mechanism. Dynamics effects may lead to new interpretations of organic
reactivity.
1 Institute of Scientific and Industrial
Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
2 Department of Chemistry, Graduate School of
Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
3 Pacific Northwest National Laboratory,
EMLS/K8-91, Battelle Boulevard, Richland, WA 99352, USA.
*
To whom correspondence should be addressed. E-mail:
yamataka{at}sanken.osaka-u.ac.jp (H.Y.);
maida{at}hiroshima-u.ac.jp (M.A.); michel.dupuis{at}pnl.gov
(M.D.)
