A comparison of the Cope rearrangements of cis-1,2-divinyleyelopropane, cis-2,3-divinylaziridine, cis-2,3-divinyloxirane, cis-2,3-divinylphosphirane, and cis-2,3-divinylthiirane: A DFT study

Transition structures, energetics, and nucleus-independent chemical shifts (NICS) for Cope rearrangements of cis-2,3-divinylaziridine (IN), cis-2,3-divinyloxirane (10), cis-2,3-divinylphosphirane JP), and cis-2,3-divinylthiirane (IS), leading to 4,5-dihydro-1H-azepine (3N), 4,5-dihydrooxepine (30), 4,5-dihydro-1H-phosphepine (W), and 4,5-dihydrothiepine (3S), respectively, are reported at the (U)B3LYP/6-31G* level and compared to those of cis-1,2-divinylcyclopropane (1C). The minimum energy path for all rearrangements proceeds through an endo-boatlike, aromatic transition structure. The predicted activation barriers increase in the order of 1C < IN < 10 < 1P < IS, which agrees qualitatively with the decreasing ring strain order of reference compounds (cyclopropane > aziridine > oxirane > phosphirane > thiirane). The exothermicities for these rearrangements decrease in the order of IN > 10 > 1C > 1P > IS. If the place of 1C in this sequence is ignored, the decreasing reaction exothermicity order correlates well with the increasing activation barrier order and with decreasing strain order of reference compounds. NICS values calculated for transition structures are typical of highly aromatic transition structures of thermally allowed pericyclic reactions.


Fam-zinc catalyzed asymmetric 1,3-dipolar cycloaddition reactions of azomethine ylides and
Koyuncu, Hasan; Doğan, Özdemir; Department of Chemistry (2007)
In the first part of this study, four new chiral ligands (FAM) were synthesized and used in catalytic amounts in asymmetric 1,3-dipolar cycloaddition reactions of azomethine ylides. This method leads to the synthesis of chiral pyrrolidines, which are found in the structure of many biologically active natural compounds and drugs. It was found that using 10 mol% of one of these chiral ligands with different dipolarophiles (dimethyl maleate, dimethyl fumarate, methyl acrylate, tert-butyl acrylate, and Nmethylm...
Synthesis of 1,2,3,5- tetrasubstituted pyrrole derivatives via 5-exo-dig type cyclization and stereoselective functionalisation of ferrocene derivatives
Kayalar, Metin; Demir, Ayhan Sıtkı; Department of Chemistry (2005)
A convenient and new method for the synthesis of 1,2,3,5-tetrasubstituted pyrrole derivatives starting from 1,3,-dicarbonyl compounds through acid catalyzed cyclization reaction is described. Alkylation of 1,3-dicarbonyl compound with propargyl bromide followed by one step cyclization with the introduction of primary amines in the presence of catalytic amount of triflouroacetic acid (TFA) affords the corresponding pyrrole derivatives in high yields. The investigations on the studies of developing a new meth...
Asymmetric synthesis of N-aryl substituted chiral 1,4-aminoalcohol derivatives and applications in various asymmetric transformation reactions
Odabaş, Serhat; Tanyeli, Cihangir; Department of Chemistry (2007)
The asymmetric synthesis of N-aryl substituted chiral 1,4-aminoalcohols and their applications in asymmetric borane reduction and enantioselective diethylzinc addition to benzaldehyde reactions were performed starting from meso-anhydride 51 that is the cycloadduct of cyclopentadiene and maleic anhydride. The desymmetrization of meso-anhydride 51 was achieved by using quinine or quinidine with very high enantiomeric excess value (up to 98% ee) and with high chemical yield. The quinine-mediated desymmetrizati...
Chemoenzymatic synthesis of enantiomerically enriched 2-oxobicyclo[m.1.0]alkan-3-yl acetate derivatives
Atlı, Selin; Tanyeli, Cihangir; Department of Chemistry (2005)
a,β-Unsaturated cyclic ketones were selectively oxidized on a'- positions using Mn(OAc)3 and Pb(OAc)4, respectively. The resultant racemic a'-acetoxylated substrates were resolved into corresponding enantiomerically enriched a'-hydroxylated and a'-acetoxylated compounds via PLE hydrolysis. a'-Hydroxylated compounds are racemized quickly, so they were acetylated with acetyl chloride and pyridine in situ to give the corresponding a'-acetoxylated compounds. Resultant a'-acetoxy a,β-unsaturated cyclic ketones r...
Addition of 1,3-dicarbonyl compounds to the cycloheptatriene derivatives
Südemen, M. Burak; Balcı, Metin; Department of Chemistry (2009)
The one electron oxidant Mn(OAc)3 has been used for years for the oxidative addition of 1,3-dicarbonyls to alkenes to give dihydrofuranes. Since cycloheptatriene is in equilibrium with its valance isomer norcaradiene, it will be interesting to study the reaction of CHT derivatives with Mn(OAc)3 in the presence of 1,3-dicarbonyls. In our research, we have observed that unsubstituted cycloheptatriene gave CHT based products. However, when electron withdrawing -CN group was attached to C-7 position of CHT we o...
Citation Formats
M. Zora, “A comparison of the Cope rearrangements of cis-1,2-divinyleyelopropane, cis-2,3-divinylaziridine, cis-2,3-divinyloxirane, cis-2,3-divinylphosphirane, and cis-2,3-divinylthiirane: A DFT study,” JOURNAL OF ORGANIC CHEMISTRY, pp. 6018–6026, 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48475.