title: Mechanistic investigation of the nickel-catalyzed Suzuki reaction of N,O-acetals: evidence for boronic acid assisted oxidative addition and an iminium activation pathway.
abstract: The mechanism of a recently reported Suzuki coupling reaction of quinoline-derived allylic N,O-acetals has been studied using a combination of structural, stereochemical, and kinetic isotope effect experiments. The data indicate that C-O activation is facilitated by Lewis acid assistance from the boronic acid coupling partner and an ionic S(N)1-like mechanism accounts for oxidative addition. In this context, we demonstrate the first direct observation of oxidative addition to a quinolinium salt. Notably, this mechanism is distinct from the more commonly described S(N)2(')-type oxidative addition of low-valent transition metals to most allylic electrophiles.
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Sylvester
authors.forename: Kevin
authors.initials: K
authors.lastname: Wu
authors.forename: Abigail G
authors.initials: AG
authors.lastname: Doyle
mesh_terms: D000080:Acetals / Q000737:chemistry*; D001897:Boronic Acids / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000080:Acetals; D001897:Boronic Acids; D009942:Organometallic Compounds; D011804:Quinolines; D009532:Nickel