Competing Isomerizations: A Combined Experimental/Theoretical Study of Phenylpentenone Isomerism

Autor:	Andrew G. H. Wee, Zhongyi Wang, Steven S. Hepperle, Allan L. L. East, Ron G. TrebleR.G. Treble
Rok vydání:	2006
Předmět:	Work (thermodynamics) Chemistry Computational chemistry Diastereomer Proton NMR Thermodynamics Density functional theory Physical and Theoretical Chemistry Isomerization Spectral line
Zdroj:	The Journal of Physical Chemistry A. 110:5985-5989
ISSN:	1520-5215 1089-5639
Popis:	The possible competition of Z/E versus hydrogen-shift isomerization in (E)-5-phenyl-3-penten-2-one (E-1) and (E)-5-phenyl-4-penten-2-one (E-2) was studied, both experimentally and theoretically. Iodine-catalyzed isomerization experiments and computational modeling studies show that the equilibrated system consists predominantly of E-1 and E-2, with E-2 in moderate excess, and with no detectable amounts of the Z (cis) diastereoisomers. Density functional theory (DFT) calculations corroborated the free energy difference (Delta(r) and Delta(r) were -0.7 and -1.1 kcal mol(-1), respectively), and computations of Boltzmann-weighted (1)H NMR spectra were found to be useful in confirming the assignment of the isomers. The relevance of this equilibrium to earlier work on double-bond stabilization is discussed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::623cc36a0aaf0e17f2e40849768259c9 https://doi.org/10.1021/jp0572075 Zobrazit plný text záznamu