A simple and convenient strategy for the synthesis of tolanophanes: Synthesis, characterization and conformational analysis of a novel tolanophane
The bromination/dehydrobromination of stilbenophanes as a practical, simple and efficient strategy is applied to the synthesis of tolanophanes 1a (n=2) and 1b (n=4). The method is significantly superior to the reported methods. A careful conformational study on a novel tolanophane 1b showed that the relative stability of its conformers is directly linked to both twist angle between the two arene rings and the orientation of the alkoxy groups. The strong interaction between 1b and CDCl3 at -60 degrees C is an unusual feature that is attributed to high restriction in its molecular motion.