Molecular-orbital calculations ring opening

Cooksy, A. L. King, H. F. Richardson, W. H. Molecular orbital calculations of ring opening... 

Nucleophilic bimolecular ring-opening of ethylene oxide by the hydride anion has been investigated theoretically. Molecular orbital calculations of the interaction energy (a combination of coulomb, exchange, delocalization, and polarization interaction terms) were carried out. The kinetics and stereochemistry of base-catalysed polymerization of epoxides have been studied using optically active epoxide monomers. 

Ford GP, Smith CT (1987) Gas-phase hydrolysis of protonated oxirane. Ab initio and semiempirical molecular orbital calculations. JAm Chem Soc 109(5) 1325-1331 Coxon JM, Maclagan DGAR, Rauk A, Thorpe AJ, Whalen D (1997) Rearrangement of protonated propene oxide to protonated propanal. J Am Chem Soc 119(20) 4712 718 Korzan R, Upton B, Turnbull K, Seybold PG (2010) Quantum chemical study of the energetics and directionality of acid-catalyzed aromatic epoxide ring openings. Int J Quant Chem 110(15) 2931 2937... 

The results of Fenske-Hall molecular orbital calculations for transition metal thiophene complexes with the ligand bound in 1)5, T l-S-bound, 1)2,1 4 t 4-S-112 and ring-opened modes have been reported335. Formation of Ti -complexes such as [Cp Ir(Ti4-2,5-diinethylthiophene)]2+ was found to be favoured by the presence of elecron-rich metal centres and also to lead to activation of the ring with respect to a ring-opening reaction via a formal oxidative addition reaction. 

Hisayoshi S (1997) Molecular orbital calculations for acid induced ring opening reaction of spiropyran. Dyes Pigm 33 229-237... 

Theoretical.—Molecular orbital calculations have been reported for the thiiranium ions derived from ethylene, propylene, isobutene, and butadiene. The most stable system involves a p-configuration of the valence electrons of sulphur. Differences in the extension of the lowest unoccupied MO s on the ethylene carbon atoms were said to be important in determining the regio-specificity of ring-opening addition reactions with chloride ion. Theoretical calculations on C2H4SH indicate that a bridged thiiranium structure would be more stable as an intermediate than an open structure in electrophilic additions of RSX to olefins. The barrier to pyramidal inversion at the sulphur atom was calculated to be 78.11 kcal mol . 

---