Ligand families

A variety of triazole-based monophosphines (ClickPhos) 141 have been prepared via efficient 1,3-dipolar cycloaddition of readily available azides and acetylenes and their palladium complexes provided excellent yields in the amination reactions and Suzuki-Miyaura coupling reactions of unactivated aryl chlorides <06JOC3928>. A novel P,N-type ligand family (ClickPhine) is easily accessible using the Cu(I)-catalyzed azide-alkyne cycloaddition reaction and was tested in palladium-catalyzed allylic alkylation reactions <06OL3227>. Novel chiral ligands, (S)-(+)-l-substituted aryl-4-(l-phenyl) ethylformamido-5-amino-1,2,3-triazoles 142,... 

Suda T, Takahashi N, Udagawa N, Jimi E, Gillespie MT, Martin TJ (1999) Modulation of osteoclast differentiation and function by the new members of the tumor necrosis factor receptor and ligand families. Endocr Rev 20 345-357... 

The results obtained with the Knowles catalyst system have led to a number of useful tools that have helped with the development of other ligand families. 

Perhaps the first successful variation of the PPFA framework was the development of the JosiPhos family of ligands (33) [125, 131, 141, 142], Here, the two phosphorus groups are attached to the same cyclopentenyl ring rather than one to each of the rings. The C2-symmetry model is now a distant memory for these ligand families. 

The success of BINAP and the associated ligands families has led to many variations, and most have shown improved properties for specific applications (Fig. 23.1). Examples include derivatives of the naphthyl system of BINAP, as well as those derived from BIPHEP. 

The josiphos ligands arguably constitute the most versatile and successful ferro-cenyl ligand family. Because the two phosphine groups are introduced in consecutive steps with very high yields (as shown in Scheme 25.1), a variety of ligands is readily available with widely differing steric and electronic properties. 

A series of chiral N,S-chelates was synthesized as ligands for the iridium(l)-catalyzed reduction of ketones using either HCOOH/NEtj or isopropanol as hydrogen sources. The ligands were obtained by sulfoxidation of an (R)-cysteine-based aminosulfide, providing a diastereomeric ligand family containing a chiral sulfur... 

One of the most significant additions to the modern rhodium] ) catalyst ligand family was the development of the hybrid catalysts that combined the carboxamide bridging ligands with the enhanced reactivity of perfluoroalkyl substituents. In this series, rhodium] ) trifluoroacetamidate [Rh2]tfa)4] was the first described [30]. n addi-... 

The QUINAPHOS Ligand Family and its Application in Asymmetric Catalysis... 

The QUINAPHOS Ligand Family/ and its Application in Asymmetric Catalysis 269 Table 2.1.5.6 Enantioselective hydrovinylation of styrene using NaBARF as activator. 

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