Transition structures and energetics for the Cope rearrangement of cis-1,2-divinylcyclobutane: an ab initio study

2003-05-05
Zora, Metin
Özkan, İlker
Transition structures and energetics for the Cope rearrangements of cis-1,2-divinylcyclobutane, obtained by RHF/6-31G* and MP2(full)/6-31G*//RHF/6-31G* calculations, are reported. Three transition structures (endo-boatlike, chairlike and exo-boatlike) have been located, giving rise to formation of cis,cis-, cis,trans- and trans,trans- 1,5-cyclooctadienes, respectively. cis-1,2-divinylcyclobutane rearranges via an endo-boatlike transition structure and yields the corresponding cis,cis product with higher exothermicity. Formation of severely strained cis,trans- and trans,trans-1,5-cyclooctadienes from this rearrangement is also discussed.
JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM

Suggestions

Transition structures and energetics for the Cope rearrangement of cis-1,2-divinylcyclopropane: an ab initio study
Zora, Metin; Özkan, İlker; Danışman, Mehmet Fatih (2003-09-30)
Transition structures and energetics for the Cope rearrangements of cis-1,2-divinylcyclopropane, obtained by RHF/6-31G* and MP2(full)/6-31G*//RHF/6-31G* calculations, are reported. Three transition structures (endo-boatlike, chairlike and exo-boatlike) have been located, giving rise to formation of cis,cis-, cis,trans- and trans,trans-1,4-cycloheptadienes, respectively. cis- 1,2-Divinylcyclopropane rearranges via an endo-boatlike transition structure and yields the corresponding cis,cis product with higher ...
Synthesis of fused tetrazolone derivatives
Ozcan, Sevil; Ekmekci, Zeynep; Mujde, Berk; Balcı, Metin (2013-01-01)
New fused tetrazolone derivatives were synthesized using homophthalic and maleic anhydrides. Treatment of anhydrides with trimethylsilyl azide opened the lactone rings and formed the corresponding intermediates, which bore 1,3-dipole and dipolarophile functionalities in ortho positions. The intermediates partially underwent internal 1,3-dipolar cycloaddition to produce fused tetrazolone derivatives. When the carbonyl groups in anhydride were not conjugated with any double bond, then a triazine-fused tetrazo...
The di-pi-methane photorearrangement of 2,3-disubstituted benzobarrelenes and benzonorbornadiene - Substituent effects in regioselectivity
Altundas, R; Dastan, A; Unaldi, NS; Guven, K; Uzun, O; Balcı, Metin (2002-02-01)
2,3-Disubstituted benzobarrelene and benzonorbornadiene derivatives 16, 17, and 18, containing electron-withdrawing and electron-donating substituents, have been synthesized and subjected to triplet-sensitized photoisomerization. Methyl 3-methyl-2-benzobarrelenecarboxylate (16) gave two di-pi-methane rearrangement products. However, methyl 3-cyano-2-benzobarrelenecarboxyidte (17) underwent an intramolecular [2(pi) + 2(pi)] cycloaddition reaction, whilst methyl 3cyano-2-benzonorbornadienecarboxylate (18) for...
Transition structures, energetics, and secondary kinetic isotope effects for cope rearrangements of cis-1,2-divinylcyclobutane and cis-1,2-divinylcyclopropane: A DFT study
Özkan, İlker; Zora, Metin (2003-12-12)
The minimum energy reaction paths and secondary kinetic isotope effects (KIE) for the Cope rearrangements of cis- 1,2-divinylcyclobutane and cis- 1,2-divinyleyclopropane obtained by (U)B3LYP calculations are reported. Both reactions proceed through endo-boatlike reaction paths, and have aromatic transition states. The predicted activation energies are in agreement with the experimental data. The reaction paths of the rearrangements are intervened by enantiomerization saddle points of the products (and the r...
Synthesis of a New 2,3-Diaminoconduritol with Conduritol F Structure
Ekmekci, Zeynep; Balcı, Metin (2012-09-01)
A new 2,3-diaminoconduritol derivative with the conduritol F structure was prepared starting from cyclohexa-1,4-diene. Initially, a lactam, prepared by the cycloaddition of chlorosulfonyl isocyanate (CSI) to cyclohexa-1,4-diene, was converted into an amino acid. The conversion of the acid functionality into an isocyanate resulted in the formation of an imidazolidinone derivative, formed by an intramolecular cyclization. In the second part of this work, the known anhydride, 3a,4,7,7a-tetrahydroisobenzofuran-...
Citation Formats
M. Zora and İ. Özkan, “Transition structures and energetics for the Cope rearrangement of cis-1,2-divinylcyclobutane: an ab initio study,” JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, pp. 251–256, 2003, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/31133.