Theoretical study on the isomerization behavior between α,β-unsaturated acyl radicals and α-ketenyl radicals

Hiroshi Matsubara*, Ilhyong Ryu, Carl H. Schiesser

*Corresponding author for this work

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

(Chemical Equation Presented) Ab initio calculations using 6-311G**, cc-pVDZ, aug-cc-pVDZ, and a (valence) double-ζ pseudopotential (DZP) basis set, with (QCISD, CCSD(T)) and without (UHF) the inclusion of electron correlation, and density functional methods (BHandHLYP, B3LYP) predict that α,β-unsaturated acyl radicals and α-ketenyl radicals exist as isomers. At the CCSD(T)/cc-pVDZ//BHandHLY/cc-pVDZ level of theory, energy barriers of 15.1 and 17.7-21.7 kJ mol -1 are calculated for the isomerization of s-trans-propenoyl and s-trans-crotonoyl radical to ketenylmethyl and 1-ketenylethyl radical, respectively. Similar results are obtained for the reactions of s-trans isomers involving silyl, germyl, and stannyl groups with energy barriers (ΔE ) of 12.2-12.4, 13.1-13.9, and 12.9-18.2 kJ mol -1 at the CCSD(T)/DZP//BHandHLYP/DZP calculation, respectively. These results suggest that α,β-unsaturated acyl radicals and α-ketenyl radicals are not canonical forms but are isomeric species that can rapidly interconvert.

Original languageEnglish
Pages (from-to)3610-3617
Number of pages8
JournalJournal of Organic Chemistry
Volume70
Issue number9
DOIs
StatePublished - 29 Apr 2005

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