(R)-1-[(S)-2-(Diphenylphosphino)ferrocenyl]ethyldi-tert-butylphosphine
[CAS# 155830-69-6]

Identification

• Classification: Catalysts and additives
• Name: (R)-1-[(S)-2-(Diphenylphosphino)ferrocenyl]ethyldi-tert-butylphosphine
• Synonyms: [(R)-1-[(S)-2-(Di-tert-butylphosphino)ferrocenyl]ethyl]diphenylphosphine
• Molecular Formula: C₃₂H₄₀FeP₂
• Molecular Weight: 542.45
• CAS Registry Number: 155830-69-6
• EC Number: 639-808-9
• SMILES: [Fe].[CH]1[CH][CH][CH][CH]1.C[C@H]([C]2[CH][CH][CH][C]2P(c3ccccc3)c4ccccc4)P(C(C)(C)C)C(C)(C)C

Safety Data

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

Discovery and Applications

(R)-1-[(S)-2-(Diphenylphosphino)ferrocenyl]ethyldi-tert-butylphosphine, commonly known as a member of the Walphos ligand family, represents a significant advancement in asymmetric catalysis. This chiral bidentate phosphine ligand was developed through the collaborative efforts of researchers seeking to overcome challenges in stereoselective catalytic transformations. The Walphos ligands were first introduced in the early 2000s, designed to optimize selectivity, stability, and efficiency in a broad range of catalytic applications. Structurally, the molecule features a ferrocenyl backbone, which imparts rigidity, and two distinct phosphine groups: a diphenylphosphino moiety and a bulky di-tert-butylphosphino group, which together create a unique steric and electronic environment.

The synthesis of (R)-1-[(S)-2-(Diphenylphosphino)ferrocenyl]ethyldi-tert-butylphosphine typically starts from ferrocene derivatives that are functionalized through lithiation and electrophilic substitution. The introduction of the chiral centers is controlled using enantioselective synthetic strategies or chiral auxiliaries to ensure high stereochemical purity. The resulting ligand is notable for its air-stability and ease of handling, making it suitable for both laboratory research and industrial-scale applications.

This ligand has demonstrated exceptional performance in various asymmetric catalytic reactions. One of its most prominent applications is in rhodium-catalyzed asymmetric hydrogenation, where it provides high enantioselectivity in the reduction of functionalized alkenes. This has been particularly valuable in the synthesis of pharmaceutical intermediates, such as chiral amines and alcohols used in the production of drugs for treating neurological disorders and cardiovascular diseases. Additionally, (R)-1-[(S)-2-(Diphenylphosphino)ferrocenyl]ethyldi-tert-butylphosphine has shown effectiveness in palladium-catalyzed asymmetric allylic alkylation, facilitating the formation of stereochemically defined carbon-carbon bonds, which are crucial for complex molecule synthesis.

The versatility of this ligand extends to hydroformylation and cross-coupling reactions, providing chemists with a powerful tool for creating molecules with precise stereochemistry. Its ability to fine-tune reactivity and selectivity through structural modifications has led to ongoing research aimed at developing new variants for specialized applications. The combination of robustness, tunable properties, and high selectivity underscores the importance of this ligand in modern asymmetric synthesis, contributing to advances in pharmaceuticals, agrochemicals, and materials science.

References

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