NUCLEAR MAGNETIC RESONANCE SPECTRA OF CIS-5,6-DISUBSTITUTED NORBORNENES . CORRELATION OF PROTON CHEMICAL SHIFTS WITH TAFT INDUCTIVE SUBSTITUENT CONSTANT

The 1H nmr spectra of exo,cis- and endo,cis-5,6-dihydroxynorbornene and exo,cis- and endo, cis- 5,6-diacetoxy norbornene have been analyzed. The chemical shifts of H7a and H78 obtained from these analyses, together with the corresponding chemical shifts of several other cis-5,6-disubstituted norbornenes whose spectra have been analyzed and reported in the literature, have been found to be linear functions of the value of the Taft inductive substituent constant for the substituents at C5 and C6. These relations show that the nature of the substituents determines whether H7a or H78 is more shielded in exo,cis-5,6-disubstituted norbornenes. © 1969, American Chemical Society. All rights reserved.