Relative reactivity of three and four membered rings ? the absence of charge effectElectronic supplementary information (ESI) available: Gaussian archive file. See http://www.rsc.org/suppdata/ob/b3/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.

Aliphatic Polyethers: Classical Polymers for the 21st Century

“…In comparison to oxirane (112 kJ mol −1 ), oxetane (106 kJ mol −1 ) exhibits a lower ring strain and is less reactive, which has to be taken into account during the polymerization process.…”

Diastereoselective Synthesis of Eight‐Membered‐Ring Allenes from Propargylic Epoxides and Aldehydes by Silylene Insertion into Carbon–Oxygen Bonds

“…Insertions of silylenes into carbon–oxygen bonds do not require release of ring strain from an epoxide 34. 35 Silylene transfer to the acylic propargyl ethers 14 a , b provided propargyl silanes 15 a , b as single regioisomers [Eq. (4)].…”

Oxetanes and Oxetenes: Fused-Ring Derivatives

“…Theoretical studies have addressed this reduction in hydrolysis rates. [38][39][40][41][42] Strain energies and equilibrium geometries of 2,4-oxytwistane 23 were computed ab initio using the MP2(fc)/6-31G(d) theoretical model and compared with oxetane. 43 The ring-strain energies (RSEs) of spiroepoxy-b-lactone 24 and spiroepoxy-oxetane 25 have been calculated from the energies of fully-optimized structures at the MP2 + ZP/cc-pVDZ level.…”