CORRELATIONS OF PROTON COUPLING CONSTANTS IN THE CYCLOPROPANE RING WITH ELECTRONEGATIVITY: CONSIDERATION OF THE PROTON RESONANCE SPECTRUM OF CYCLOPROPYLLITHIUM

Abstract

The analysis of cyclopropyllithium allows estimates to be made of all proton coupling constants. The exceptionally small couplings across carbon atoms 2 and 3 are examined in the context of correlations of coupling constants with the electronegativities of substituents. It is concluded that, although the couplings involving protons attached to the same carbon as the substituent decrease with increasing electronegativity of the substituent, the opposite is true for couplings involving the protons attached to carbons one bond removed from the substituent. Individual values are suggested for the coupling constants in cyclopropane itself and these agree with the observed I3 C side bands in its proton spectrum.