Weak-Interaction-Enabled Highly Diastereoselective Synthesis of trans-Indanes through a Palladium-Catalyzed [3 + 2] Annulation between 2-Bromoarylmethyl Ketones and Norbornenes.

A palladium-catalyzed [3 + 2] annulation of 2-bromoarylmethyl ketones and norbornenes via a benzylic C(sp3)-H activation is reported. The norbornane-fused indane products were formed in good to excellent yields with a highly diastereoselective trans configuration. Mechanistic studies, including NCI analysis, indicated weak interactions between the substrates and catalysts.