[(R)-1-[(S)-2-(Dicyclohexylphosphino)ferrocenyl]ethyl]di-tert-butylphosphine
[CAS# 158923-11-6]

Identification

• Classification: Chemical reagent >> Organic reagent >> Phosphine ligand
• Name: [(R)-1-[(S)-2-(Dicyclohexylphosphino)ferrocenyl]ethyl]di-tert-butylphosphine
• Synonyms: (2R)-1-[(1R)-1-[Bis(1,1-dimethylethyl)phosphino]ethyl]-2-(dicyclohexylphosphino)ferrocene
• Molecular Formula: C₃₂H₅₂FeP₂
• Molecular Weight: 554.55
• CAS Registry Number: 158923-11-6
• EC Number: 813-879-8
• SMILES: C[C@H]([C]1[CH][CH][CH][C]1P(C2CCCCC2)C3CCCCC3)P(C(C)(C)C)C(C)(C)C.[CH]1[CH][CH][CH][CH]1.[Fe]

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302-H315-H319-H335
• Precautionary Statements: P261-P305+P351+P338

Discovory and Applicatios

[(R)-1-[(S)-2-(Dicyclohexylphosphino)ferrocenyl]ethyl]di-tert-butylphosphine is a chiral bidentate phosphine ligand widely used in asymmetric catalysis. It belongs to the family of ferrocene-based ligands designed to optimize stereoselectivity in catalytic reactions. This compound integrates a ferrocenyl backbone with two distinct phosphine groups: a bulky di-tert-butylphosphine moiety and a dicyclohexylphosphino group. This combination offers a unique balance of steric and electronic properties, making the ligand highly versatile in facilitating enantioselective transformations.

The discovery of [(R)-1-[(S)-2-(Dicyclohexylphosphino)ferrocenyl]ethyl]di-tert-butylphosphine traces back to research efforts in the late 1990s and early 2000s focusing on improving selectivity in transition metal-catalyzed reactions. Researchers recognized the potential of incorporating ferrocenyl groups due to their rigid, planar structure and the ease with which they can be modified. The introduction of the dicyclohexylphosphino group significantly enhanced the ligand’s ability to control stereoselectivity by providing increased steric hindrance around the metal center.

This ligand is commonly synthesized through a multi-step process involving functionalization of ferrocene derivatives. The initial lithiation of the ferrocene framework allows for the introduction of a chiral alkyl chain, followed by phosphination with di-tert-butylphosphine and dicyclohexylphosphine. The resulting product is a stable, crystalline compound that can be easily stored and handled in laboratory environments.

[(R)-1-[(S)-2-(Dicyclohexylphosphino)ferrocenyl]ethyl]di-tert-butylphosphine has found significant applications in asymmetric catalysis, particularly in hydrogenation and allylic alkylation reactions. It forms highly active and selective complexes with transition metals such as rhodium, palladium, and iridium. For example, rhodium complexes derived from this ligand are used in the asymmetric hydrogenation of prochiral olefins, achieving excellent enantioselectivity. This is crucial for synthesizing chiral intermediates for pharmaceutical compounds, including drugs used to treat cardiovascular and neurological conditions.

The ligand also plays a role in palladium-catalyzed asymmetric allylic substitution, enabling the formation of stereochemically defined carbon-carbon bonds. This reaction type is essential for constructing complex molecular architectures needed in drug development and natural product synthesis. The stability, tunability, and effectiveness of [(R)-1-[(S)-2-(Dicyclohexylphosphino)ferrocenyl]ethyl]di-tert-butylphosphine have made it a valuable tool for chemists seeking precision and efficiency in asymmetric synthesis.

Ongoing research continues to explore modifications of this ligand to expand its utility in other catalytic processes. The ability to tailor its steric and electronic properties makes it a cornerstone in the development of new catalytic systems for both academic and industrial applications.