Intraannular photoreactions in pseudo-geminally substituted [2.2]paracyclophanes

Abstract

SummaryThe photoisomerization of the pseudo-geminal tetraene 11 furnishes the cyclooctadiene derivatives 13 and 15 with a completely new type of molecular bridge for a [2.2]paracyclophane which promise many interesting novel applications; the same is true for the photoisomerization of 22 to 23 and 24. The structures of these new hydrocarbons were established by X-ray crystallography and spectroscopic analysis; among the noteworthy structural features of 13 and 15 are unusually long carbon–carbon single bonds (>1.64 Å).

My Favorite Aromatic Compounds—A Tribute to Friedrich August Kekulé

“…On irradiation with a high‐pressure mercury lamp in benzene the two components form the ladderane 84 . Electrocyclic ring‐opening, which is typical for this class of hydrocarbons, then leads to a mixture of two isomers 86 , presumably via 85 as an intermediate. Both compounds 86 could be separated and fully characterized (including X‐ray structural analysis).…”

π‐Stacked Oligo(phenylene vinylene)s Based on Pseudo‐Geminal Substituted [2.2]Paracyclophanes: Impact of Interchain Geometry and Interactions on the Electronic Properties

“…As a result, there are minimal interactions between the two conjugated segments as soon as their lengths are increased.The pseudo-geminal (pg) substitution pattern of [2.2]paracyclophane holds substituents on each ring directly atop one another. Such stacking of conjugated units leads to facile intramolecular photochemical cycloadditions, [4][5][6][7] and new electronic transitions in multi-decker stacks. [8] The opportunity to prepare new materials containing the cyclophane core has recently attracted increased attention.…”