Proton magnetic resonance and stereochemistry of some 5,6-disubstituted bicyclo[2.2.2]oct-2-enes and their oxidation products

Proton Magnetic Resonance Spectra and Stereochemistry of Some 5,6-Disubstituted Bicyclo[2.2.2]oct-2-enes

“…I with the aromatic group endo to the double bond. This is in contrast to the results obtained from the reaction of trans-p-chloro-p-nitrostyrene with 1,3-cyclohexadiene, in which case the isomer with the aromatic group exo to the double bond was obtained in largest amount (1).…”

“…Thus, structure XI is established for the oxidation product of the major adduct and this in turn establishes structure I for the main adduct. It is also of interest that spectrum A is very similar to the NMR spectrum of the corresponding 3-nitro compound (1 In compounds I and I1 (Fig. 2).…”

“…Thus, structure XI is established for the oxidation product of the major adduct and this in turn establishes structure I for the main adduct. It is also of interest that spectrum A is very similar to the NMR spectrum of the corresponding 3-nitro compound (1). endo and exo Proton Signal Shifts on Hydrogenation.-The long-range shielding effects resulting from the magnetic anisotropy of the ethylene group have been recognized for some time (3).…”