Enantioselective Gold(I) Catalysis with Chiral Monodentate Ligands

Enantioselective gold(I) catalysis is receiving a growing level of credit in the field of asymmetric synthesis. After a pioneering work in the mid-1980s the area remained almost silent for several years, until densely substituted diphosphine chiral ligands were disclosed as competent chiral units for gold-catalyzed stereoselective manipulation of unactivated unsaturated hydrocarbons. The chemistry of alkynes, allenes and most recently also alkenes received significant benefits from the latter developments. More recently, ad hoc designed chiral monodentate ligands have risen to prominence in producing robust, highly tunable (electronic and steric) and efficient chiral cationic mononuclear gold species for asymmetric transformations. In this scenario, electron-deficient phosphorus-based (i.e., phosphoramidites, phosphites) but also axially chiral electron-rich carbene ligands deserve particular mention and the corresponding applications will be summarized herein.