title: N-Heterocyclic carbene-catalyzed annulation of α-cyano-1,4-diketones with ynals.
abstract: In this paper, the first stereoselective annulation reaction between α-cyano-1,4-diketones and ynals, mediated by catalytic amounts of a triazolium salt precatalyst and cocatalytic amounts of a weak carboxylate base, is disclosed. The title transformation proceeds smoothly under mild reaction conditions and generates three contiguous stereogenic centers, one of which is a quaternary acetal carbon. This reaction tolerates a wide variety of electronically distinct substituents on both reaction partners and affords privileged bicyclic scaffolds in 61-90% isolated yields and with up to 20:1 diastereomeric preference.
authors.affiliation: Department of Organic Chemistry, University of Geneva, quai Ernest Ansermet 30, CH-1211 Geneva 4, Switzerland.
authors.forename: Fedor
authors.initials: F
authors.lastname: Romanov-Michailidis
authors.forename: Céline
authors.initials: C
authors.lastname: Besnard
authors.forename: Alexandre
authors.initials: A
authors.lastname: Alexakis
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D007659:Ketones / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D007659:Ketones; D009570:Nitriles; C030011:carbene; D008697:Methane