31538-14-4

Upstream product

• 110-91-8 morpholine 
• 95-66-9 2,4-dimethylchlorobenzene 
• 108-38-3 m-xylene 
• 583-70-0 1-bromo-2,4-dimethylbenzene 

Relevant academic research and scientific papers

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.

Aryl-Diadamantyl Phosphine Ligands in Palladium-Catalyzed Cross-Coupling Reactions: Synthesis, Structural Analysis, and Application

Synthesis, temperature-dependent NMR structure investigation and utilization of a new, stable and easily accessible aryl-diadamantylphosphine ligand family is reported. The bulky and electron-rich phosphorus center of the ligand enhances the catalytic activity of palladium in cross-coupling reactions of sterically demanding ortho-substituted aryl halides. In our study, we demonstrated the synthetic applicability of the new phosphine ligands in Buchwald-Hartwig and tosyl hydrazone coupling reactions.

Copper-Catalyzed para-Selective C-H Amination of Electron-Rich Arenes

A one-pot two-step method for para-selective C-H amination of carbocyclic arenes comprises the in situ formation of unsymmetrical diaryl-λ3-iodanes followed by their Cu(I)-catalyzed reaction with a range of N-unprotected amines.

Palladium-catalyzed aminations of aryl halides with phosphine- functionalized imidazolium ligands

A series of 1-(2-diphenylphosphinoferrocenyl)ethyl-3-substituted imidazolium iodides [3-substituent = methyl (1a); isopropyl (1b); tert-butyl (1c); 1-adenosyl (1d); cyclohexyl (1e); 2,6-dimethylphenyl (1f); 2,4,6-trimethylphenyl (1g); 2,6-diisopropylphenyl (1h)] have been prepared and evaluated as ligands in the palladium-catalyzed aminations of aryl halides with various amines. The scope of the coupling process was carried out for various aryl bromides and chlorides with the catalysts generated in situ from a mixture of Pd(OAc)2 and 1 in the presence of a base. NaOtBu was found the choice of base in combination with dioxane, toluene, or DME as solvent, although NaOH or Cs2CO3 promoted the coupling of 4-bromotoluene with morpholine in moderate conversion. The steric hindrance from the 3-substituent of imidazolium in the hybrid-bidentate chelating system was found to be only beneficial to the substrates without ortho-substituents. The more sterically hindered 1d or 1h promoted the coupling of bromobenzene with morpholine in nearly quantitative conversion with 0.2 mol% of palladium loading in the presence of NaOtBu at 110°C, and 94% of conversion was afforded with the less sterical demanding 1a for a longer time. However, for the substrates with ortho-substituents, higher conversions were achieved with 1a. The Pd(OAc)2/1d catalytic system was also active for deactivated aryl chloride, and 71% isolated yield for the desired product was realized for coupling of 4-chloroanisole with morpholine at 2 mol% of catalyst loading. The developed catalyst system has been applied successfully to the synthesis of a key building block for a type of functional polymers. The Royal Society of Chemistry.