Diastereoselective Synthesis of Indane Scaffolds via Acid‐Mediated Cascade Cyclization

Indanes are privileged bicyclic architectures in bioactive molecules and are ubiquitous in many pharmaceuticals and natural products. A simple, efficient acid‐mediated domino reaction between o ‐cinnamylated chalcones and 2,6‐diisopropylphenol leading to indanes is reported. The reaction proceeds stereoselectively to furnish a highly diastereoselective indane possessing three consecutive stereocenters in good to excellent yields (up to 91%). This approach applies to a wide range of chalcones and is easy to operate. An initial intramolecular cyclization triggered by the nucleophilic double bond of o‐cinnamyl group onto β‐position of enone part of chalcone moiety followed by an intermolecular Friedel–Crafts reaction of 2,6‐diisopropylphenol with incipient carbocation furnished the final product. The remarkable diastereocontrol may be attributed to steric factors.