Efficient palladium-catalyzed Suzuki-Miyaura coupling of aryl chlorides with arylboronic acids using benzoferrocenyl phosphines as supporting ligands

Four monodentate benzoferrocenyl phosphines were studied as supporting ligands in palladium-catalyzed Suzuki-Miyaura coupling of aryl chlorides with arylboronic acids. Of these ligands, the more electron-rich and steric demanding benzoferrocenyl dicyclohexyl phosphine was found highly effective for the reaction followed by the benzoferrocenyl diisopropyl phosphine. The corresponding diethyl and diphenyl phosphines are much less active. When the dicyclohexyl phosphine was used, both electron-rich and electron-poor aryl chlorides were coupled with arylboronic acids within 1 h giving good to excellent yields. Chloro-substituted pyridines were also found highly reactive under these conditions giving excellent yields of biaryl products. Sterically hindered biaryls can also be prepared using the dicyclohexyl phosphine as ligand.     

Enantioselective Synthesis of Atropisomeric Vinyl Arene Compounds by Palladium Catalysis: A Carbene Strategy

An efficient palladium‐catalyzed asymmetric synthesis of axially chiral vinyl arenes from aryl bromides and hydrazones is reported. The products were easily oxidized to axially chiral biaryl compounds, and the phosphine oxides were readily reduced to phosphine ligands.     

Rapid synthesis of an electron-deficient t-BuPHOX ligand: cross-coupling of aryl bromides with secondary phosphine oxides

Herein an efficient and direct copper-catalyzed coupling of oxazoline-containing aryl bromides with electron-deficient secondary phosphine oxides is reported. The resulting tertiary phosphine oxides can be reduced to prepare a range of PHOX ligands. The presented strategy is a useful alternative to known methods for constructing PHOX derivatives.     

3-Aryl-2-oxazolidinones through the palladium-catalyzed N-arylation of 2-oxazolidinones

[reaction: see text] 3-Aryl-2-oxazolidinones are obtained in good yields through the palladium-catalyzed N-arylation of 2-oxazolidinones with aryl bromides. The nature of aryl bromides, phosphine ligands, bases, and solvents strongly affects the reaction outcome.     

钯等过渡金属催化的卤代芳烃和胺的偶联反应

综述了钯等过渡金属催化的卤代芳烃或芳基碘酸酯和胺的偶联反应以及催化这 一新反应的催化剂的发展和应用。用于该反应的配体由P（o-tolyl)3发展到BINAP 及二烷基芳基膦，基底物由溴代芳烃扩展到经济易得的氯化芳烃及碘酸酯和各种胺。     

Phosphine‐Directed CH Borylation Reactions: Facile and Selective Access to Ambiphilic Phosphine Boronate Esters

Ambiphilic ligands have received considerable attention over the last two decades due to their unique reactivity as organocatalysts and ligands. The iridium‐catalyzed C? H borylation of phosphines is described in which the phosphine is used as a directing group to provide selective formation of arylboronate esters with unique scaffolds of ambiphilic compounds. A variety of aryl and benzylic phosphines were subjected to the reaction conditions, selectively providing stable, isolable boronate esters upon protection of the phosphine as the borane complex. After purification, the phosphine‐substituted boronate esters could be deprotected and isolated in pure form.     

Phosphine‐Directed C?H Borylation Reactions: Facile and Selective Access to Ambiphilic Phosphine Boronate Esters

Ambiphilic ligands have received considerable attention over the last two decades due to their unique reactivity as organocatalysts and ligands. The iridium‐catalyzed C H borylation of phosphines is described in which the phosphine is used as a directing group to provide selective formation of arylboronate esters with unique scaffolds of ambiphilic compounds. A variety of aryl and benzylic phosphines were subjected to the reaction conditions, selectively providing stable, isolable boronate esters upon protection of the phosphine as the borane complex. After purification, the phosphine‐substituted boronate esters could be deprotected and isolated in pure form.     

New preparation of alkyl- and aryl-mono-η5-cyclopentadienylphosphine compounds or iron,cobalt and nickel

Tertiary phosphine stabilized homoleptic alkyl and aryl compounds of Fe, Co and Ni undergo protonolysis of their MC bonds with cyclopentadiene to produce the corresponding mono-η⁵-cyclopentadienyl complexes. Initial low reaction temperatures and the presence of phosphine ligands prevent the formation of metallocenes. This method allows the easy introduction of various achiral and chiral ligands into complexes of this class.     

Practical synthesis of new and highly efficient ligands for the Suzuki reaction of aryl chlorides

A practical synthesis of a novel class of phosphine ligands, phosphino substituted N-aryl pyrroles (PAP ligands), has been developed. These ligands are applied in the palladium-catalyzed coupling of a variety of aryl and heteroaryl chlorides with phenylboronic acid showing exceedingly high turnover numbers at mild reaction temperatures and even at room temperature.     

Copper catalyzed arylation of urea

An efficient copper catalyzed amidation of aryl iodides with urea is described. This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligands.     

Determination of equilibrium constants and computational interaction energies for adducts of [Rh2(RCO2)(4-n)(PC)n] (n = 0-2) with Lewis bases

Properties of dirhodium catalysts with cyclometalated aryl phosphine ligands have been studied. We report here the study of the acid-base reaction of Rh2(RCO2)2(PC)2(H2O)2 catalysts (PC = cyclometalated aryl phosphine) with different Lewis bases. The determination of the equilibrium constants of these reactions can be used to study to which extent the properties of the axial coordination site of the catalyst, considered the active site, are affected by modification of the metalated phosphines, the carboxylate ligands, or the incoming axial ligand. The trends in the computational density functional theory interaction energies show good agreement with the major trends in the equilibrium constants, thus enabling a further study of the influence of the modification of the ligand core.     

Transition metal catalyzed cross-coupling of aryl Grignard reagents with aryl fluorides via Pd- or Ni-activation of the C-F bond: an efficient synthesis of unsymmetrical biaryls - application of microwave technology in ligand and catalyst screening

Biaryl compounds are prevalent in both nature and in active pharmaceutical ingredients. The palladium and nickel catalyzed cross-coupling of aryl Grignard reagents with aryl fluorides reported herein affords moderate to excellent yields of the corresponding unsymmetrical biaryls. In addition, the first example of a biaryl cross-coupling utilizing unactivated aryl fluorides under phosphine free palladium conditions is reported. Microwave technology allowed rapid optimization of catalyst systems, which identified several ligands for this cross-coupling reaction.     

Bulky alkylphosphines with neopentyl substituents as ligands in the amination of aryl bromides and chlorides

Di(tert-butyl)neopentylphosphine (DTBNpP) in combination with palladium sources provided catalysts with comparable or better activity for the Hartwig-Buchwald amination of aryl bromides than tri(tert-butyl)phosphine (TTBP) under mild conditions. DTBNpP also provided effective catalysts for amination reactions of aryl chlorides at elevated temperatures. Further replacement of tert-butyl groups with neopentyl substituents resulted in less effective ligands for amination reactions. Computationally derived cone angles showed that replacement of a tert-butyl group with a neopentyl group significantly increased the cone angle of the phosphine. The larger cone angle of DTBNpP than TTBP appears to correlate with the higher activity of catalysts derived from DTBNpP in the amination of aryl bromides. TTBP is a stronger electron donor than DTBNpP, which may explain the higher activity for TTBP-derived catalysts toward aryl chlorides.     

A facile and modular synthesis of phosphinooxazoline ligands

The copper(I) iodide catalyzed phosphine/aryl halide coupling procedure of Buchwald et al. provides modular, robust, and scaleable access to phosphinooxazoline (PHOX) ligands. The advantages of this method are highlighted by the convenient synthesis of PHOX ligands with varied steric and electronic properties, which would be challenging to synthesize by other protocols.     

A bowl-shaped phosphine as a ligand in palladium-catalyzed Suzuki-Miyaura coupling of aryl chlorides: effect of the depth of the bowl

[reaction: see text] Bowl-shaped phosphine ligands were found to be highly effective in Suzuki-Miyaura coupling of unactivated aryl chlorides, in which the depth of the bowl affected the catalytic activity considerably.     

A Highly Active Ylide‐Functionalized Phosphine for Palladium‐Catalyzed Aminations of Aryl Chlorides

Ylide‐functionalized phosphine ligands (YPhos) were rationally designed to fit the requirements of Buchwald–Hartwig aminations at room temperature. This ligand class combines a strong electron‐donating ability comparable to NHC ligands with high steric demand similar to biaryl phosphines. The active Pd species are stabilized by agostic C?H???Pd rather than by Pd–arene interactions. The practical advantage of YPhos ligands arises from their easy and scalable synthesis from widely available, inexpensive starting materials. Benchmark studies showed that YPhos‐Pd complexes are superior to the best‐known phosphine ligands in room‐temperature aminations of aryl chlorides. The utility of the catalysts was demonstrated by the synthesis of various arylamines in high yields within short reaction times.     

Suzuki-Miyaura coupling of aryl tosylates catalyzed by an array of indolyl phosphine-palladium catalysts

A family of indolyl phosphine ligands was applied to Suzuki-Miyaura cross-coupling of aryl tosylates. Catalyst loading can be reduced to 0.2 mol % for coupling of nonactivated aryl tosylate. A challenging example for room temperature coupling is realized. The scope of this highly active Pd/L2 system can be extended to other boron nucleophiles, including trifluoroborate salts and boronate esters. The ligand structural comparisons toward the reactivity in tosylate couplings are also described.     

Easily Accessible Benzamide‐Derived P,O Ligands (Bphos) for Palladium‐Catalyzed Carbon–Nitrogen Bond‐Forming Reactions

Easily accessible benzamide‐derived hemilabile phosphine ligands were efficiently prepared through ortho‐directed lithiation of the corresponding N,N‐diethylbenzamide followed by quenching with chlorodialkylphosphines. These structurally simple hemilabile ligands were found to be highly effective in palladium‐catalyzed amination of aryl and heteroaryl chlorides. Various sterically congested and functionalized aryl halide substrates were compatible in these reaction conditions. By using optimized reaction conditions, remarkable catalyst productivity (total turnover number up to 8400) was obtained.     

A family of simple amide-derived air-stable P,O-ligands for Suzuki cross-coupling of unactivated aryl chlorides

A family of air-stable amide-derived phosphine (Aphos) ligands engineered on simple N,N-dialkyl aryl amide scaffolds has been designed and prepared by one-pot synthesis from the amides in high yields. The Aphos ligands have been used, in analogous to their atropisomeric variations, as hemilabile bidentate P,O-ligands in various Pd-catalyzed C-N and C-C bond forming reactions. We present here our results on the highly efficient Suzuki cross-coupling reactions of unactivated and/or sterically hindered aryl chlorides with arylboronic acids and a relationship of Aphos structures with catalytic efficacy.     

Palladium‐Catalyzed Enantioselective Synthesis of 2‐Aryl Cyclohex‐2‐enone Atropisomers: Platform Molecules for the Divergent Synthesis of Axially Chiral Biaryl Compounds

The palladium‐catalyzed asymmetric synthesis of enone‐based atropisomers from 2‐iodo‐3‐methylcyclohex‐2‐enones and aryl boronic acid is reported. BoPhoz‐type phosphine–aminophosphine ligands showed superior enantioselectivity over other ligands. These cyclohexenone‐based atropisomers are useful compounds for further elaboration. The divergent synthesis of biaryl atropisomers with different ortho substituents was demonstrated.