Ephos
[CAS# 2118959-55-8]

Identification

• Classification: Organic raw materials >> Aryl compounds >> Biphenyl compounds
• Name: Ephos
• Synonyms: Dicyclohexyl(3-isopropoxy-2',4',6'-triisopropyl-[1,1'-biphenyl]-2-yl)phosphine
• Molecular Formula: C₃₆H₅₅OP
• Molecular Weight: 534.80
• CAS Registry Number: 2118959-55-8
• SMILES: CC(C)C1=CC(=C(C(=C1)C(C)C)C2=C(C(=CC=C2)OC(C)C)P(C3CCCCC3)C4CCCCC4)C(C)C

Properties

• Melting point: 161-162 ºC

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319
• Precautionary Statements: P264-P280-P302+P352-P337+P313-P305+P351+P338-P362+P364-P332+P313

Discovory and Applicatios

Ephos is a ligand derived from phosphines, specifically designed for use in organometallic chemistry, particularly in catalysis. The discovery of Ephos marked a significant advancement in ligand design, offering unique properties that have been widely exploited in various catalytic processes. Its name, "Ephos," typically represents a class of phosphine ligands that are often characterized by the presence of ether groups attached to the phosphine backbone, contributing to their distinct chemical behavior.

The development of Ephos ligands was driven by the need for ligands that could enhance the efficiency and selectivity of catalytic reactions, especially in the formation of carbon-carbon and carbon-heteroatom bonds. Traditional phosphine ligands had limitations in terms of steric and electronic properties, which often affected the outcome of catalytic reactions. Ephos ligands, with their carefully engineered structures, offered a solution by providing a balance of steric bulk and electronic tuning.

Ephos ligands are particularly notable for their application in palladium-catalyzed cross-coupling reactions, such as the Suzuki-Miyaura, Heck, and Stille reactions. In these reactions, Ephos ligands have demonstrated the ability to stabilize the palladium center, thereby increasing the turnover number and rate of the catalytic process. This results in higher yields and improved selectivity, making these ligands highly valuable in both academic research and industrial applications.

One of the key features of Ephos ligands is their ability to facilitate challenging reactions, including those involving sterically hindered substrates. The presence of ether groups in the ligand structure introduces flexibility and modulates the electron density at the phosphorus atom, which in turn affects the reactivity of the metal center. This unique combination of properties allows Ephos ligands to participate in a variety of catalytic cycles, often outperforming traditional phosphine ligands.

Beyond cross-coupling reactions, Ephos ligands have found use in other catalytic transformations, such as hydrogenation, carbonylation, and C-H activation. Their versatility is attributed to their tunable nature, allowing chemists to modify the ligand structure to suit specific reaction conditions and desired outcomes. This adaptability has made Ephos ligands a staple in the toolkit of synthetic chemists, particularly in the development of complex molecules in the pharmaceutical and fine chemical industries.

In addition to their practical applications, Ephos ligands have also contributed to the fundamental understanding of ligand effects in catalysis. Studies involving Ephos ligands have provided insights into how subtle changes in ligand structure can influence reaction mechanisms, stability of catalytic intermediates, and overall catalytic efficiency. This knowledge has been instrumental in guiding the design of new ligands with tailored properties for specific catalytic applications.

In summary, the discovery and development of Ephos ligands represent a significant milestone in the field of catalysis. Their unique structural features and versatile applications have made them indispensable in modern synthetic chemistry. As research in ligand design continues to evolve, Ephos ligands will likely remain a key component in the development of new catalytic processes, driving innovation in both academic and industrial settings.