Tandem Cyclization/Hydroarylation of α,ω-Dienes Triggered by Scandium-Catalyzed C-H Activation

A highly regio- and diastereoselective cyclization/hydroarylation reaction of 1,5- and 1,6-dienes with aromatic ethers and tertiary anilines was established by a cationic 2-picoline-tethered-half-sandwich scandium alkyl catalyst, which constitutes a process for producing a diverse array of cis-1,3-disubstituted arylated and trans-1,2-disubstituted benzylated methylcyclopentane derivatives in one step with 100% atom-efficiency. Furthermore, a mechanism involving a scandium-catalyzed aromatic ortho-C-H activation and alkene-insertion cascade was also proposed.