Homolytic aromatic substitution of heterocyclic compounds. Part III. Structural analysis of dihydro-derivatives formed by reaction of phenylazotriphenylmethane with furan and benzene

Abstract

The structural analysis of the two 2,5-dihydro-2-phenyl-5-triphenylmethylfuran isomers obtained from the decomposition of phenylazotriphenylmethane in furan has been carried out with the help of some deuteriated derivatives by n.m.r. spectroscopy. The cis-structure has been assigned to the higher-melting isomer on the basis of the higher field shift of the ortho-protons of the phenyl group and the lower field shift of the vinyl proton in the 2-position. The assignment is also confirmed by the observed coupling constants in the two isomers. On the same basis, the configurational assignment of the two isomeric 1,4-dihydro-4-triphenylmethylbiphenyls has been confirmed.