title: Highly enantioselective cyclizations of conjugated trienes with low catalyst loadings: a robust chiral N-heterocyclic carbene enabled by acetic acid cocatalyst.
abstract: Densely functionalized cyclopentenones are useful synthetic intermediates. We report herein a new method to synthesize this important class of compounds through a highly enantioselective (98 → 99% ee) triene cyclization that is cocatalyzed by acetic acid and a chiral N-heterocyclic carbene (NHC). We discovered that acetic acid not only could coexist with NHCs but also could greatly stabilize the active catalyst, which enables a long-lived catalyst with high reactivity and selectivity.
authors.affiliation: Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303, USA.
authors.forename: Guansai
authors.initials: G
authors.lastname: Liu
authors.forename: Phillip D
authors.initials: PD
authors.lastname: Wilkerson
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Toth
authors.forename: Hao
authors.initials: H
authors.lastname: Xu
mesh_terms: D019342:Acetic Acid / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006571:Heterocyclic Compounds / Q000737:chemistry*; D007700:Kinetics; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D006571:Heterocyclic Compounds; C030011:carbene; D008697:Methane; D019342:Acetic Acid