415941-54-7Relevant articles and documents
Iron phosphine catalyzed cross-coupling of tetraorganoborates and related group 13 nucleophiles with alkyl halides
Bedford, Robin B.,Brenner, Peter B.,Carter, Emma,Clifton, Jamie,Cogswell, Paul M.,Gower, Nicholas J.,Haddow, Mairi F.,Harvey, Jeremy N.,Kehl, Jeffrey A.,Murphy, Damien M.,Neeve, Emily C.,Neidig, Michael L.,Nunn, Joshua,Snyder, Benjamin E. R.,Taylor, Joseph
, p. 5767 - 5780 (2015/02/19)
Iron phosphine complexes prove to be good precatalysts for the cross-coupling of alkyl, benzyl, and allyl halides with not only aryl triorganoborate salts but also related aluminum-, gallium-, indium-, and thallium-based nucleophiles. Mechanistic studies revealed that while Fe(I) can be accessed on catalytically relevant time scales, lower average oxidation states are not formed fast enough to be relevant to catalysis. EPR spectroscopic studies reveal the presence of bis(diphosphine)iron(I) complexes in representative catalytic reactions and related processes with a range of group 13 nucleophiles. Isolated examples were studied by M?ssbauer spectroscopy and single-crystal X-ray structural analysis, while the electronic structure was probed by dispersion-corrected B3LYP DFT calculations. An EPR study on an iron system with a bulky diphosphine ligand revealed the presence of an S = 1/2 species consistent with the formation of a mono(diphosphine)iron(I) species with inequivalent phosphine donor environments. DFT analysis of model complexes allowed us to rule out a T-shaped Fe(I) structure, as this is predicted to be high spin.
A highly versatile catalyst system for the cross-coupling of aryl chlorides and Amines
Lundgren, Rylan J.,Sappong-Kumankumah, Antonia,Stradiotto, Mark
experimental part, p. 1983 - 1991 (2010/07/03)
The syntheses of 2-(di-tertbutylphosphino)-N,N-dimethylaniline (L1, 71%) and 2-(di-1-adamantylphosphino)-N,N-dimethylaniline (L2, 74%), and their application in BuchwaldHartwig amination, are reported. In combination with [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2, these structurally simple and air-stable P,N ligands enable the cross-coupling of aryl and heteroaryl chlorides, including those bearing as substituents enolizable ketones, ethers, esters, carboxylic acids, phenols, alcohols, olefins, amides, and halogens, to a diverse range of amine and related substrates that includes primary alkyl- and arylamines, cyclic and acyclic secondary amines, N-H imines, hydrazones, lithium amide, and ammonia. In many cases, the reactions can be performed at low catalyst loadings (0.5-0.02 mol % Pd) with excellent functional group tolerance and chemoselectivity. Examples of cross-coupling reactions involving 1,4-bromochlorobenzene and iodobenzene are also reported. Under similar conditions, inferior catalytic performance was achieved when using Pd(OAc)2, PdCl2, [PdCl2(cod)] (cod = 1,5-cyclooctadiene), [PdCl 2(MeCN)2], or [Pd2(dba)3] (dba = dibenzylideneacetone) in combination with L1 or L2, or by use of [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2 with variants of L1 and L2 bearing less basic or less sterically demanding substituents on phosphorus or lacking an ortto-dimethylamino fragment. Given current limitations associated with established ligand classes with regard to maintaining high activity across the diverse possible range of C-N coupling applications, L1 and L2 represent unusually versatile ligand systems for the cross-coupling of aryl chlorides and amines
