Dicyclohexylphenylphosphine
[CAS# 6476-37-5]

Identification

• Classification: Organic raw materials >> Organic phosphine compound
• Name: Dicyclohexylphenylphosphine
• Synonyms: Dicyclohexyl phenyl phosphine
• Molecular Formula: C₁₈H₂₇P
• Molecular Weight: 274.38
• CAS Registry Number: 6476-37-5
• EC Number: 229-334-7
• SMILES: C1CCC(CC1)P(C2CCCCC2)C3=CC=CC=C3

Properties

• Melting point: 60-61 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302
• Safety Statements: P264-P270-P301+P317-P330-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319

Discovery and Applications

Dicyclohexylphenylphosphine is a versatile organophosphorus compound that has gained significant attention due to its wide range of applications in organic synthesis and catalysis. The compound, characterized by its robust steric bulk and electron-donating properties, plays a crucial role in various chemical transformations, particularly in transition metal-catalyzed reactions. The discovery and utilization of Dicyclohexylphenylphosphine reflect the ongoing development of phosphine ligands tailored for specific catalytic processes.

The synthesis of Dicyclohexylphenylphosphine can be traced back to the development of phosphine chemistry in the mid-20th century. The compound is typically synthesized by the reaction of chlorodiphenylphosphine with cyclohexylmagnesium bromide, followed by hydrolysis. This process yields a phosphine ligand that is both sterically demanding and electronically rich, making it an ideal candidate for stabilizing transition metal centers in catalytic cycles.

The structural features of Dicyclohexylphenylphosphine contribute to its effectiveness as a ligand in transition metal complexes. The bulky cyclohexyl groups provide significant steric hindrance, which can influence the coordination environment around the metal center. This steric bulk can help to prevent unwanted side reactions, thereby enhancing the selectivity of the catalytic process. Additionally, the phenyl group in the phosphine contributes to the electronic properties of the ligand, offering a balance between electron donation and steric effects.

One of the most prominent applications of Dicyclohexylphenylphosphine is in palladium-catalyzed cross-coupling reactions, such as the Suzuki-Miyaura and Heck reactions. In these reactions, the phosphine ligand plays a critical role in stabilizing the palladium center, facilitating the formation of carbon-carbon bonds between aryl halides and organoboron compounds or alkenes. The steric bulk of the dicyclohexyl groups helps to modulate the reactivity of the palladium catalyst, improving the efficiency and selectivity of the coupling process.

In addition to palladium-catalyzed reactions, Dicyclohexylphenylphosphine is also utilized in nickel-catalyzed cross-coupling reactions, where it serves as a ligand to enhance the reactivity and stability of nickel complexes. These nickel-catalyzed processes are particularly valuable for the formation of carbon-heteroatom bonds, such as carbon-nitrogen and carbon-oxygen bonds, which are essential in the synthesis of pharmaceuticals and fine chemicals.

Dicyclohexylphenylphosphine has also found application in rhodium-catalyzed hydroformylation reactions, where it acts as a ligand to control the regioselectivity of aldehyde formation. In hydroformylation, the choice of phosphine ligand is crucial for determining the ratio of linear to branched aldehydes produced. The steric properties of Dicyclohexylphenylphosphine can be tuned to favor the formation of either linear or branched products, depending on the desired outcome.

Furthermore, Dicyclohexylphenylphosphine is employed in asymmetric catalysis, where its steric and electronic properties are leveraged to induce chirality in the product molecules. In asymmetric hydrogenation, for example, the phosphine ligand is used to create a chiral environment around the metal center, leading to the formation of enantiomerically enriched products. The ability to control stereochemistry through the use of chiral phosphine ligands has made Dicyclohexylphenylphosphine an important tool in the synthesis of chiral pharmaceuticals and other biologically active compounds.

Beyond its role in catalysis, Dicyclohexylphenylphosphine is also used in the synthesis of organometallic complexes for materials science applications. The compound can be incorporated into metal-organic frameworks (MOFs) and other coordination polymers, where its bulky phosphine ligand helps to dictate the architecture and porosity of the material. These materials have potential applications in gas storage, separation technologies, and catalysis.

The use of Dicyclohexylphenylphosphine in these various applications underscores its importance as a phosphine ligand with a unique combination of steric and electronic properties. Its ability to stabilize transition metal centers, control selectivity in catalytic processes, and induce chirality in asymmetric synthesis makes it a valuable reagent in both academic research and industrial chemistry. As the field of phosphine ligand design continues to evolve, Dicyclohexylphenylphosphine remains a key player in the development of new catalytic methodologies and materials.

References

2009. Di-μ-iodido-bis{[dicyclohexyl(phenyl)phosphine-κP](pyridine-κN)silver(I)}. Acta crystallographica. Section E, Structure reports online, 65(4).
DOI: 2969050

2017. Parameterization of phosphine ligands demonstrates enhancement of nickel catalysis via remote steric effects. Nature Chemistry, 9(7).
DOI: 5609847

2017. Preparation of Aryl(dicyclohexyl)phosphines by C-P Bond-Forming Cross-Coupling in Water Catalyzed by an Amphiphilic-Resin-Supported Palladium Complex. Synlett, 28(17).
DOI: 10.1055/s-0036-1590926