title: Stereodivergency of triazolium and imidazolium-derived NHCs for catalytic, enantioselective cyclopentane synthesis.
abstract: Chiral triazolium- and imidazolium-derived N-heterocyclic carbene catalysts promote the direct annulation of alpha,beta-unsaturated aldehydes and achiral alpha-hydroxy enones to afford cyclopentane-fused lactones with high enantioselectivity. Remarkably, otherwise structurally identical imidazolium and triazolium precatalysts afford different major products. These studies provide both an efficient entry to valuable chiral structures and a dramatic demonstration of stereodivergency of chiral imidazolium versus triazolium-derived N-heterocyclic carbene catalysts.
authors.affiliation: Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
authors.forename: Juthanat
authors.initials: J
authors.lastname: Kaeobamrung
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Bode
mesh_terms: D002384:Catalysis; D003500:Cyclization; D003517:Cyclopentanes / Q000138:chemical synthesis* / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism; D014230:Triazoles / Q000737:chemistry*
chemical_list: D003517:Cyclopentanes; D007093:Imidazoles; D014230:Triazoles