title: An examination of the palladium/Mor-DalPhos catalyst system in the context of selective ammonia monoarylation at room temperature.
abstract: An examination of the [{Pd(cinnamyl)Cl}(2)]/Mor-DalPhos (Mor-DalPhos = di(1-adamantyl)-2-morpholinophenylphosphine) catalyst system in Buchwald-Hartwig aminations employing ammonia was conducted to better understand the catalyst formation process and to guide the development of precatalysts for otherwise challenging room-temperature ammonia monoarylations. The combination of [{Pd(cinnamyl)Cl}(2)] and Mor-DalPhos afforded [(κ(2)-P,N-Mor-DalPhos)Pd(η(1)-cinnamyl)Cl] (2), which, in the presence of a base and chlorobenzene, generated [(κ(2)-P,N-Mor-DalPhos)Pd(Ph)Cl] (1 a). Halide abstraction from 1 a afforded [(κ(3)-P,N,O-Mor-DalPhos)Pd(Ph)]OTf (5), bringing to light a potential stabilizing interaction that is offered by Mor-DalPhos. An examination of [(κ(2)-P,N-Mor-DalPhos)Pd(aryl)Cl] (1 b-f) and related precatalysts for the coupling of ammonia and chlorobenzene at room temperature established the suitability of 1 a in such challenging applications. The scope of reactivity for the use of 1 a (5 mol %) encompassed a range of (hetero)aryl (pseudo)halides (X = Cl, Br, I, OTs) with diverse substituents (alkyl, aryl, ether, thioether, ketone, amine, fluoro, trifluoromethyl, and nitrile), including chemoselective arylations.
authors.affiliation: Department of Chemistry, Dalhousie University, 6274 Coburg Road, PO Box 15000, Halifax, Nova Scotia B3H 4R2, Canada.
authors.forename: Pamela G
authors.initials: PG
authors.lastname: Alsabeh
authors.forename: Rylan J
authors.initials: RJ
authors.lastname: Lundgren
authors.forename: Robert
authors.initials: R
authors.lastname: McDonald
authors.forename: Carin C C
authors.initials: CC
authors.lastname: Johansson Seechurn
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Colacot
authors.forename: Mark
authors.initials: M
authors.lastname: Stradiotto
mesh_terms: D000588:Amines / Q000737:chemistry*; D000641:Ammonia / Q000737:chemistry*; D002384:Catalysis; D056831:Coordination Complexes / Q000737:chemistry*; D006219:Halogens / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D013696:Temperature
chemical_list: D000588:Amines; D056831:Coordination Complexes; D006219:Halogens; D007659:Ketones; D013440:Sulfides; D010165:Palladium; D000641:Ammonia