Ir-Catalyzed Atroposelective Desymmetrization of Heterobiaryls: Hydroarylation of Vinyl Ethers and Bicycloalkenes.

A highly regio, diastereo- and enantioselective, scalable Ir-catalyzed hydroarylation of electron rich acyclic and tensioned cyclic olefins with heterobiaryls is described. The reaction of acyclic vinyl ethers, dihydrofuran and norbornenes with a variety of aryl isoquinoline, quinazo-line, and picoline derivatives takes place with simultaneous installation of central and axial chirality, reaching complete branched/linear or exo/endo ratios and excellent diastereo- and enantiomeric excesses when in situ formed [IrI/Tol-SDP] or [IrI/Tol-BINAP] complexes are used as the catalysts. Kinetic isotope effect (KIE) analyses and a comprehensive computational study suggest that, despite fast double bond migratory insertion into Ir-H, the reaction proceeds through a modified Chalk-Harrod mechanism, starting with selectivity-determining insertion into Ir-CAryl. The regioselectivity is controlled by the electron donating alkoxy group, whereas diastereo- and enanti-oselectivity have a complex origin, that depend on the relative orientation of the alkoxy group and the establishment of adequate π-π interactions between the biaryl and the phosphine.