Pattillo Christopher C, Strambeanu Iulia I, Calleja Pilar, Vermeulen Nicolaas A, Mizuno Tomokazu, White M Christina
Roger Adams Laboratory, Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States.
J Am Chem Soc. 2016 Feb 3;138(4):1265-72. doi: 10.1021/jacs.5b11294. Epub 2016 Jan 25.
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.
报道了在钯（II）/双亚砜/布朗斯特碱催化下的一种高效需氧线性烯丙基C-H胺化反应。该反应在制备条件下操作简单（1当量烯烃，1个大气压的氧气或空气），钯（II）/双亚砜催化剂负载量降低，同时与使用化学计量的苯醌（BQ）作为终端氧化剂的体系相比，具有更高的周转率和产物收率。钯（II）/BQ的π-酸性相互作用已在各种催化过程中被提及，并且通常被认为有利于促进还原官能化。然而，当不需要这种用于官能化的亲电活化时，高浓度的BQ可能会与关键配体（双亚砜）结合竞争并抑制催化作用。动力学研究揭示了反应速率与BQ浓度之间的反比关系，表明BQ作为钯（II）的配体，对催化产生抑制作用。
