Syntheses and Spectral Properties of Norbornadiene-Fused Heterocycles: 1,3-Diphenyl-4,7-dihydro-4,7-methanobenzo[c]thiophene, -4,7-methano-2H-isoindole, and -4,7-methanoisobenzofuran

The syntheses of a novel diphenyl-substituted thiophene, pyrrole, and furan fused at the 3- and 4-positions with norbornadiene are described. Structures of these molecules are discussed on the basis of spectral properties by comparison with those of cyclohexene-fused derivatives. Single crystal X-ray structural analysis of the norbornadiene-fused thiophene as well as the PM3 calculations of the related compounds revealed that the bond angles of carbon atoms at the ring-junction of norbornadiene-fused heterocycles are distorted.