Gold(I)-Catalyzed Enantioselective Polycyclization Reactions

Polycyclization reactions of unsaturated molecules allow for the rapid construction of complex structures in a single operation.1 Thus, numerous methods that proceed with excellent diastereose-lectivity have been developed over the past 50 years.2 In contrast, enantioselective variants are rare and the majority of reported examples involve cyclization cascades that are promoted by reactions of alkenes with electrophillic reagents.3,4 Given that the substrates contain mul-tiple alkenes, initiating polycyclization reactions through selective activation of an alkyne5,6 offers the potential advantage of circumvent-ing unwanted reactions resulting from nonselective alkene activation; however, an example of an enantioselective polycyclization reaction of alkynes has yet to be reported. Given that the majority of polycyclization reactions have been induced by an endocyclic process, we first evaluated the use of chiral phosphinegold(I) complexes in a 6-endo-dig initiated poly