Unprecedented simultaneous quantum tunneling reaction discovered

Amazing stuff! I am not sure what the implications are, but it may open up new discoveries etc.

"Two conformers of the same molecule react independently to form a different rearrangement product rather than taking the much lower energy barrier pathway of interconverting into the other conformer, chemists have discovered. The unprecedented process, entirely controlled by quantum tunneling, ‘is completely breaking the classic transition state rules’ ... Understanding what and how tunneling controls chemical reactivity could be ‘a game changer for selectivity’ ..."

From the abstract:

"We present here a new example of chemical reactivity governed by quantum tunneling, which also highlights the limitations of the classical theories. The syn and anti conformers of a triplet 2-formylphenylnitrene, generated in a nitrogen matrix, were found to spontaneously rearrange to the corresponding 2,1-benzisoxazole and imino-ketene, respectively. The kinetics of both transformations were measured at 10 and 20 K and found to be temperature-independent, providing clear evidence of concomitant tunneling reactions (heavy-atom and H-atom). Computations confirm the existence of these tunneling reaction pathways. Although the energy barrier between the nitrene conformers is lower than any of the observed reactions, no conformational interconversion was observed. These results demonstrate an unprecedented case of simultaneous tunneling control in conformer-specific reactions of the same chemical species. The product outcome is impossible to be rationalized by the conventional kinetic or thermodynamic control."

Unprecedented simultaneous quantum tunnelling reaction discovered | Research | Chemistry World

Simultaneous Tunneling Control in Conformer-Specific Reactions (no public access)

Two conformers of 2-formylphenylnitrene can undergo two different quantum tunnelling processes, leading to two different products. Hydrogen atom tunnelling results in the formation of an imino-ketene (top) from the anti conformer and tunnelling involving an oxygen and nitrogen atom in the syn conformer produces a 2,1-benzisoxazole (bottom)