FeCl3 mediated synthesis of substituted indenones by a formal [2+2] cycloaddition/ring opening cascade of o-keto-cinnamates

A novel FeCl3 mediated formal [2+2] cycloaddition/ring opening cascade of o-keto-cinnamates was developed for the synthesis of indenones. The reaction tolerates a broad range of functional groups, including bromide, chloride, amide, acid and ester groups.