“Push–Pull π+/π–” (PPππ) systems in catalysis

Abstract

This computational and experimental study represents a case where “push–pull π+/π–” (PPππ) systems have shown a concrete application in chemistry apart from spectral tuning. The most notable finding of this investigation was that a mode of interaction unprecedented in catalysis, a PPππ system, played a crucial role in the Henry reaction catalyzed by a NOBIN-based squaramide. The results show that the PPππ system stabilizes the most favorable pathway, P1, with 2.7–4.7 kcal/mol. This is vital for the differentiation in energy of P1 over the remaining pathways and directly affects both the reactivity and stereoselectivity of this reaction. These results suggest that PPππ systems are promising tools with great potential for catalysis.