title: Kinetics studies of rapid strain-promoted [3 + 2]-cycloadditions of nitrones with biaryl-aza-cyclooctynone.
abstract: Strain-promoted cycloadditions of cyclic nitrones with biaryl-aza-cyclooctynone (BARAC) proceed with rate constants up to 47.3 M(-1) s(-1), this corresponds to a 47-fold rate enhancement relative to reaction of BARAC with benzyl azide and a 14-fold enhancement over previously reported strain promoted alkyne-nitrone cycloadditions (SPANC). Studies of the SPANC reaction using the linear free energy relationship defined by the Hammett equation demonstrated that the cycloaddition reaction has a rho value of 0.25 ± 0.04, indicating that reaction is not sensitive to substituents and thus should have broad applicability.
authors.affiliation: Steacie Institute for Molecular Sciences, National Research Council Canada, 100 Sussex Drive, Ottawa, Canada.
authors.forename: Craig S
authors.initials: CS
authors.lastname: McKay
authors.forename: Mariya
authors.initials: M
authors.lastname: Chigrinova
authors.forename: Jessie A
authors.initials: JA
authors.lastname: Blake
authors.forename: John Paul
authors.initials: JP
authors.lastname: Pezacki
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D001372:Aza Compounds / Q000737:chemistry*; D001386:Azides / Q000737:chemistry; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D009589:Nitrogen Oxides / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D000480:Alkynes; D001372:Aza Compounds; D001386:Azides; D009589:Nitrogen Oxides; C015388:nitrones