Acta Crystallographica Section C
The structure of 9-phenyl-3,4,4a,9a-tetrahydrotriptycene, C26H22, (I), exhibits regiochemistry consistent with a stepwise mechanism for its formation from photocycloaddition of 1,3- cyclohexadiene and 9-phenylanthracene. Bond distances involving the bridgehead C atoms are similar in (I) and the hydrogenated derivative, 9-phenyl-1,2,3,4,4a,9a-hexahydrotriptycene, C26H24, (II), with bonds to the quaternary-C atoms exhibiting significant elongation [1.581 (2) A Ê in (I) and 1.585 (2) A Ê in (II)]. The molecular geometry precludes significant overlap between the phenyl groups and the interannular bonds in both compounds, indicating that the origin of the bond lengthening is steric in nature.
Duan, S., Baker, R. J., & Masnovi, J. (January 01, 2000). 9-Phenyl-3,4,4a,9a-tetrahydrotriptycene and 9-phenyl-1,2,3,4,4a,9a-hexahydrotriptycene. Acta Crystallographica Section C Crystal Structure Communications, 56, 99-101.