title: Aerobic Linear Allylic C-H Amination: Overcoming Benzoquinone Inhibition.
abstract: An efficient aerobic linear allylic C-H amination reaction is reported under palladium(II)/bis-sulfoxide/Brønsted base catalysis. The reaction operates under preparative, operationally simple conditions (1 equiv of olefin, 1 atm O2 or air) with reduced Pd(II)/bis-sulfoxide catalyst loadings while providing higher turnovers and product yields than systems employing stoichiometric benzoquinone (BQ) as the terminal oxidant. Pd(II)/BQ π-acidic interactions have been invoked in various catalytic processes and are often considered beneficial in promoting reductive functionalizations. When such electrophilic activation for functionalization is not needed, however, BQ at high concentrations may compete with crucial ligand (bis-sulfoxide) binding and inhibit catalysis. Kinetic studies reveal an inverse relationship between the reaction rate and the concentration of BQ, suggesting that BQ is acting as a ligand for Pd(II) which results in an inhibitory effect on catalysis.
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Pattillo
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: Iulia I
authors.initials: II
authors.lastname: Strambeanu
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: Pilar
authors.initials: P
authors.lastname: Calleja
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: Nicolaas A
authors.initials: NA
authors.lastname: Vermeulen
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Mizuno
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: M Christina
authors.initials: MC
authors.lastname: White