Transition-metal-free C-C σ-bond activation of α-aryl ketones and subsequent Zn-catalyzed intramolecular cyclization: synthesis of tetrasubstituted furans

A highly atom-economical protocol for the synthesis of tetrasubstituted furans has been developed. This process is realized through the tandem reactions of Cs 2 CO 3 promoted C-C σ-bond activation of α-aryl ketones followed by Zn-catalyzed intramolecular cyclization. This represents the first example for the preparation of tetrasubstituted furans through rearrangement of molecular skeletons and subsequent transformations. Mild reaction conditions and readily accessible starting materials make the protocol attractive in organic synthesis. Atom-economical synthesis of tetrasubstituted furans from α-aryl ketones and alkynones through base-promoted cleavage of unstrained C-C single bonds of ketones and subsequent Zn-catalyzed cyclization.