Diastereoselective Synthesis of Indanes and Tetralins via Intramolecular Friedel–Crafts Reaction

An easy access to tetralin and indane skeletons has been developed using a diastereoselective intramolecular Friedel–Crafts alkylation. Treatment of diastereomeric mixtures of benzyl carbinols with a catalytic amount of Ca(NTf₂)₂/Bu₄NPF₆ yields the respective tetralin or indane in good yields with high levels of regio- and diastereoselectivity