Enantioselective Platinum-Catalyzed Tandem Hydroarylation-Cycloisomerization of 1,6-Enynes

The platinum(II) chloride/silver hexafluoroantimonate (PtCl2/AgSbF6) catalytic system associated with atropisomeric ligand Ph-BI-NEPINE promotes a stereoselective tandem hydroarylation (Friedel-Crafts-type addition) of electron-rich aromatic and heteroaromatic derivatives to un-activated alkenes followed by a C-C bond cyclization reaction (ee up to 96%). Some evidence shows that the catalytic species responsible for the highest enantiomeric excesses might reasonably be an L3Pt2+ species, L being a monodentate ligand.