Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

• Josué M. Silla,
• Rodrigo A. Cormanich,
• Roberto Rittner and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2013, 9, 1127–1134, doi:10.3762/bjoc.9.125

• ∙∙∙F hydrogen bond in 1 is quite stabilizing and dictates the 1hJF,H(O) coupling constant. Moreover, electron donation to the empty p orbital of boron (for noncoplanar BH2 moiety relative to the phenyl ring) is also significantly stabilizing for the NH2 and PH2 derivatives, but not enough to make the

• OH∙∙∙F hydrogen bonds as the governing interaction of the conformational equilibrium and, consequently, of the observed 1hJF,H(O) coupling constant [9]. However, it has been recently found that such coupling in this compound and in 2-fluorophenol itself is better described as 1TSJF,H(O), because of a

Conformational analysis, stereoelectronic interactions and NMR properties of 2-fluorobicyclo[2.2.1]heptan-7-ols

• Fátima M. P. de Rezende,
• Marilua A. Moreira,
• Rodrigo A. Cormanich and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2012, 8, 1227–1232, doi:10.3762/bjoc.8.137

• intramolecular hydrogen bond in the syn-exo isomer. It was found through NBO and AIM analyses that such an interaction contributes to structural stabilization and that the 1hJF,H(O) coupling constant in the syn-exo isomer is modulated by the nF→σ*OH interaction, i.e., the quantum nature of the F∙∙∙HO hydrogen

• bond. Keywords: conformational analysis; 2-fluorobicyclo[2.2.1]heptan-7-ols; hydrogen bond; 1hJF,H(O) coupling constant; quantum-chemical calculations; Introduction Intra- and intermolecular hydrogen bonds (HB) play an important role in determining the molecular arrangements and properties, as well