title: A practical synthesis of 3-acyl cyclobutanones by [2 + 2] annulation. Mechanism and utility of the Zn(II)-catalyzed condensation of α-chloroenamines with electron-deficient alkenes.
abstract: New conditions for the conversion of simple tertiary amides to α-chloroenamines and their use in Zn(II)-catalyzed cycloaddition reactions with commercial α,β-unsaturated carbonyl compounds allows rapid, regiocontrolled access to 3-acyl cyclobutanones. Reactions take place at ambient temperature without solvent, giving strained [2 + 2] adducts with all-carbon-substituted quaternary carbon atoms. Ab initio calculations of the putative keteniminium intermediate and studies with styrenyl olefins suggest a dual role for Zn(OTf)(2) during catalysis.
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Jeannette M
authors.initials: JM
authors.lastname: O'Brien
authors.forename: Jason S
authors.initials: JS
authors.lastname: Kingsbury
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D002074:Butanones / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D004579:Electron Transport; D004583:Electrons; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D015032:Zinc / Q000737:chemistry*
chemical_list: D000475:Alkenes; D000588:Amines; D002074:Butanones; D015032:Zinc