A facile access to indene frameworks through condensation of substituted cinnamylaldehydes and sulfonylamines under the catalysis of FeCl3 is reported.
A metal-free Brønsted acid promoted two-component reaction between cinnamaldehydes and sulfonamides is described. This cascade process provides a simple and atom-economical alternative synthesis of a range of functionalized indenes from easily available starting materials. The resulting N-indenylsulfonamides were readily converted into the corresponding indenylenamines or indanones.