Synthesis and Characterization of Hexafluorocyclopentane‐Bridged Bisbutatrienes as Models for Longer Cumulenes: Various Transformations for the Construction of π‐Conjugated Frameworks

Abstract

AbstractCumulenes have attracted considerable attention due to their unique structural and electronic properties. Despite their high potential for constructing condensed π‐conjugated molecules, the synthetic utility of longer cumulenes remains to be established owing to their inherently high reactivity. Conjugated bisbutatrienes having two cumulene moieties linked by a spacer as a mimic of a longer cumulene were evaluated. Here, the synthesis and characterization of hexafluorocyclopentane‐bridged bisbutatrienes are described. These bisbutatrienes underwent various cyclizations, to construct the unique π‐extended frameworks inaccessible by other methodologies. The bisbutatrienes were converted into fulvenes, pentalene, germacycle, and benzocyclobutene under various conditions. Furthermore, a cyclooctatetraene derivative was synthesized by a one‐step dimerization of the bisbutatriene.