Substituenteneffekte in den 13C‐NMR‐Spektren von diastereomeren Chalkondihalogeniden. VIII. Untersuchungen an α‐ und β‐Halogendihydrochalkonen und Berechnung von 13C‐chemischen Verschiebungen bei diastereomeren Chalkondihalogeniden und Chalkonhalogenhydrinen

Abstract

Substituent Effects in 13C‐N.M.R. Spectra of Diastereomeric Chalcone Dihalogenides. VIII. Investigations of α‐ and β‐Halogene Dihydrochalcones and Calculation of 13C‐chemical Shifts of Diastereomeric Chalcone Dihalogenides and Chalcone HalogenohydrinsThe chemical shifts of C‐α and C‐β in the 13C‐n.m.r. spectra are determined and compared with calculated values from an incremental system and Taft relationship. The correlations are extended for erythro and threo isomers of halohydrins and diastereometric dihalogenides 6–18.The chemical shifts of C‐α and C‐β atoms of 6–18 are described in the dependence of the shifts calculated by an incremental system. Excellent correlations allowed the computation of chemical shifts of C‐α and C‐β for diastereomeric α,β‐disubstituted dihydrochalcone derivatives likely 6–18 in advance.