Stereoelectronic effects: Perlin effects in cyclohexane‐derived compounds. (2nd December 2020)

• Record Type: Journal Article
• Authors: Jung, Sebastian T.; Nickisch, Roman; Reinsperger, Tony; Luy, Burkhard; Podlech, Joachim
• Is Part Of: Journal of physical organic chemistry. Volume 34:Number 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-02
• Subjects: coupling constants -- cyclohexane derivatives -- DFT calculations -- NBO analysis -- spiro compounds -- stereoelectronic effects; Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.4165
• Languages: English
• ISSNs: 0894-3230

Abstract

Abstract: Stereoelectronic effects in cyclohexanones, methylenecyclohexanes, spiro, and epoxy compounds of cyclohexanes and further derivatives were investigated by measuring 1 J C, H coupling constants and by identification of Perlin effects, that is, of differences in the coupling constants for equatorial and axial CH bonds in the methylene groups of six‐membered rings. The Perlin effects were correlated with results from natural bond orbital analyses. NMR experiments and calculations were performed with conformationally restricted 4‐ tert ‐butyl‐substituted derivatives. It turned out that the coupling constants are strongly influenced not only by stereoelectronic interactions with CC, CO, and CN π bonds, or with the π‐type CC or CO bonds of the three‐membered rings, but also by the s character of the respective CH bonds' carbon orbital. Reliable correlations of measured and calculated coupling constants were achieved with B3LYP/6‐311++G(d, p) and BP86/aug‐cc‐pVTZ‐J functionals. Abstract : Equatorial and axial hydrogens in methylene groups of cyclohexane derivatives and related spiro compounds show differing coupling constants (Perlin effects) dependent on the adjacent functional groups. The coupling constants are influenced by stereoelectronic effects.