Post‐Cycloaddition–Retroelectrocyclization Transformations of Polycyanobutadienes

The thermal [2+2] cycloaddition–retroelectrocyclization (CA‐RE) reaction between a range of alkynes, activated by electron‐donating anilino ( p ‐H 2 NC 6 H 4 ‐) substituents, and the electron‐deficient olefins tetracyanoethene (TCNE) and 7,7,8,8‐tetracyano‐ p ‐quinodimethane (TCNQ) delivered anilino‐substituted polycyanobutadienes (PCBDs). The aniline NH 2 groups provide a convenient handle for further transformations, yielding a new series of PCBDs without an electron‐donating group. Electrochemical investigations by rotating disk voltammetry and cyclic voltammetry revealed large anodic shifts in both the first and second reduction potentials as a result of the removal of the electron‐donating functionality. This methodology allows for PCBD‐containing substrates to be further elaborated, generating a new family of chromophores previously inaccessible by alternative synthetic methods.