Relative reactivity of three and four membered rings--the absence of charge effect

Joel L Wolk; Milon Sprecher; Harold Basch; Shmaryahu Hoz

doi:10.1039/b314869f

Relative reactivity of three and four membered rings--the absence of charge effect

Org Biomol Chem. 2004 Apr 7;2(7):1065-9. doi: 10.1039/b314869f. Epub 2004 Mar 8.

Authors

Joel L Wolk¹, Milon Sprecher, Harold Basch, Shmaryahu Hoz

Affiliation

¹ Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel 52900.

PMID: 15034630
DOI: 10.1039/b314869f

Abstract

Radical (neutral) and electrophilic (cationic) ring opening reactions were studied computationally in order to probe the difference in reactivity between three and four membered rings. Using the Marcus equation we have shown that the activation energy for the four membered ring opening is close to the Marcus predicted barrier whereas three membered rings display much higher reactivity than that predicted by the Marcus equation. Thus, the reactivity of the three membered rings is enhanced, in addition to the strain release, by another factor which is not operative in the four membered rings. It is clear also that this factor is not charge dependent. The possible origin of this effect is discussed.