Enantioselective iridium-catalyzed carbon–carbon and carbon–nitrogen bond formations
Formation of new C–C bonds is a mainstay of modern molecule construction, however methods for the asymmetric construction of these scaffolds has been limited by the use of premetalated reagents or the use of catalytic methods that still require the use of stoichiometric metallic reductants. The Krische group’s approach to this bond formation utilizes the concepts of transfer hydrogen and carbonyl addition to form C–C bonds. These processes proceed through the in situ formation of a transient allylmetal species which then undergoes carbonyl addition. The research presented herein describes the development of several methods for the enantioselective construction of new C–C bonds, utilizing allenes to form nucleophilic allylmetal complexes that react with carbonyl electrophiles. Additionally, a method for the enantioselective construction of new C–N bonds is described, utilizing branched allylic acetates to form allylmetal complexes that react in an electrophilic manner with non-redox active primary and secondary amine nucleophiles.