Base-mediated benzannulation of α-cyanocrotonates with ynones: facile synthesis of benzonitriles and fluorenes

Benzonitriles and cyanofluorenes have been rapidly obtained via the [3 + 3] benzannulation of readily available alkynones and α-cyanocrotonates using KO^tBu as the only reagent and EtOH (and CO₂) is the only by-product.