Fused Furan Moieties from Enol-like Compounds and β-Keto Sulfoxonium Ylides Involving sp C-H Activation and Concomitant Tandem C-O Annulation.

An efficient and fascinating protocol has been devised for the preparation of fused furan moieties involving a Rh(II) catalyzed one-pot C-H activation/concomitant tandem annulation process, employing an enolic compound and β-keto sulfoxonium ylide as the reacting conjugates. The developed technique demands only Rh(TFA) as the catalyst to proceed forward and is devoid of additional metallic or nonmetallic additives. The skeletal transformation of naphthoquinone fused furan to highly decorated naphthoquinone fused indolizines is a promising synthetic application.