AgSbF6-Promoted Divergent Synthesis of Highly Substituted Indene Derivatives from Methylenecyclopropane and Aroyl Chlorides

When 2,2-diphenylmethylenecyclopropane was reacted with aroyl chlorides in 1,2-dichloroethane (DCE) at 35 °C in the presence of AgSbF6, indene derivatives were obtained through a cascade process involving cyclopropane ring-opening and five-membered-ring formation. Electron-rich and moderately electron-deficient aroyl chlorides afforded 2,3-disubstituted 1H-indene derivatives, whereas strongly electron-deficient or sterically demanding aroyl chlorides selectively furnished 2,3,6-trisubstituted 1H-indene derivatives. This AgSbF6-promoted divergent reaction provides efficient and selective access to highly substituted indene derivatives.