Azulene-substituted butadiynes have been prepared by Cu-mediated cross- and homo-coupling reactions. The azulene-substituted butadiynes reacted with tetracyanoethylene in a formal [2 + 2] cycloaddition reaction to afford the corresponding 1,1,4,4-tetracyanobutadiene chromophores, in excellent yields. Further [2 + 2] cycloaddition with TTF and TCNE gave novel donor–acceptor chromophores and novel azulene-substituted 6,6-dicyanofulvene derivatives.
Organic & Biomolecular Chemistry
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