Primary Anion-π Catalysis and Autocatalysis

Epoxide-opening ether cyclizations are shown to occur on pi-acidic aromatic surfaces without the need of additional activating groups and with autocatalytic amplification. Increasing activity with the intrinsic pi acidity of benzenes, naphthalenediimides (NDIs) and perylenediimides (PDIs) support that anion-pi interactions account for function. Rate enhancements maximize at 270 for anion-pi catalysis on fullerenes and at 5100 M-1 for autocatalysis. The occurrence of anion-pi autocatalysis is confirmed with increasing initial rates in the presence of additional product. Computational studies on autocatalysis reveal transition state and product forming a hydrogen-bonded noncovalent macrocycle, like holding their hands and dancing on the active pi surface, with epoxide opening and nucleophile being activated by anion-pi interactions and hydrogen bonds to the product, respectively.