Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/64530
Type: Artigo de periódico
Title: ELECTRONIC INTERACTIONS IMPLIED BY THE NONADDITIVITY OF C-13 SUBSTITUENT PARAMETERS IN 2-SUBSTITUTED CYCLOHEXANONES
Author: BASSO, EA
KAISER, C
RITTNER, R
LAMBERT, JB
Abstract: The carbon-13 chemical shifts were assigned for all ring positions in cyclohexanone and 4-tert-butylcyclohexanone with H, F, Cl, Br, I, MeO, MeS, MeSe, Me(2)N, Me or tert-butyl in the 2-position. The substituent-induced shifts were calculated by difference from unsubstituted cyclohexanone or 4-tert-butylcyclohexanone. Both stereoisomers (cis and trans) were available for the 4-tert-butylcyclohexanones in all but one case. Comparison of the substituent-induced shifts for the cis (equatorial 2-substituent) and trans (axial 2-substituent) isomers provides stereochemical insight into the interactions between the 2-substituent and the carbonyl group that bring about non-additivity of the substituent effects. In the 2-equatorial isomer, the dipole-dipole interaction between the functional groups causes non-additivities for the C-2 carbon that depend largely on the electronegativity of the 2-substituent. In the 2-axial isomer, hyperconjugation or other orbital interactions between the groups cause non-additivities for the C-2 carbon that depend largely on the polarizability in addition to the electronegativity of the 2-substituent.
Subject: NMR
C-13 NMR
O-17 NMR
CYCLOHEXANONES
ORBITAL INTERACTIONS
POLAR EFFECTS
SUBSTITUENT-INDUCED SHIFTS
Country: Inglaterra
Editor: John Wiley & Sons Ltd
Rights: fechado
Identifier DOI: 10.1002/mrc.1260320403
Date Issue: 1994
Appears in Collections:Unicamp - Artigos e Outros Documentos

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