2-(Diphenylphosphino)benzoic acid
[CAS# 17261-28-8]

Identification

• Classification: Organic raw materials >> Organic phosphine compound
• Name: 2-(Diphenylphosphino)benzoic acid
• Molecular Formula: C₁₉H₁₅O₂P
• Molecular Weight: 306.30
• CAS Registry Number: 17261-28-8
• EC Number: 241-293-7
• SMILES: C1=CC=C(C=C1)P(C2=CC=CC=C2)C3=CC=CC=C3C(=O)O

Properties

• Melting point: 177-181 ºC

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302-H315-H319-H332-H335
• Precautionary Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P317-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H332
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H302
Skin sensitization	Skin Sens.	1	H317
Specific target organ toxicity - repeated exposure	STOT RE	1	H372
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411

Discovory and Applicatios

2-(Diphenylphosphino)benzoic acid, often abbreviated as DPPA, is a versatile compound in the field of organometallic chemistry and catalysis. This chemical substance combines the properties of a phosphine ligand with a carboxylic acid functional group, making it a valuable tool in various chemical reactions and applications. Its discovery and development have significantly impacted asymmetric synthesis, catalysis, and materials science.

The chemical structure of 2-(Diphenylphosphino)benzoic acid consists of a benzoic acid moiety substituted with a diphenylphosphino group. The phosphino group imparts excellent ligand properties, while the carboxylic acid group provides additional functionality. This combination allows for the creation of robust and versatile transition metal complexes, which are crucial in numerous catalytic processes.

The discovery of 2-(Diphenylphosphino)benzoic acid is attributed to advancements in organophosphorus chemistry, where researchers sought to develop ligands with enhanced steric and electronic properties. The ability to fine-tune the electronic environment around a transition metal center is critical in catalysis, and the introduction of diphenylphosphino groups offered a significant improvement over previous ligands.

The primary application of 2-(Diphenylphosphino)benzoic acid is in asymmetric synthesis, particularly in the field of asymmetric catalysis. In this context, the compound serves as a chiral ligand, which is essential for the selective formation of chiral molecules. Asymmetric catalysis involves the use of chiral catalysts to produce enantiomerically pure compounds, which are vital in the pharmaceutical industry for the synthesis of drug molecules with specific stereochemistry.

One notable application of 2-(Diphenylphosphino)benzoic acid is in asymmetric hydrogenation reactions. These reactions, which involve the addition of hydrogen to unsaturated compounds, are facilitated by transition metal complexes with DPPA as a ligand. The compound’s ability to form stable and active metal complexes results in high enantioselectivity and efficiency, making it an important tool for producing chiral products.

In addition to asymmetric hydrogenation, 2-(Diphenylphosphino)benzoic acid is used in cross-coupling reactions, such as the Suzuki-Miyaura reaction. This reaction, which forms carbon-carbon bonds between organic substrates, benefits from the use of DPPA-based catalysts. The compound's steric and electronic properties enhance the reactivity and selectivity of the palladium catalysts commonly employed in these reactions.

The synthesis of 2-(Diphenylphosphino)benzoic acid involves several steps, starting with the preparation of diphenylphosphine and its subsequent reaction with benzoic acid derivatives. The reaction conditions are carefully controlled to ensure the formation of high-purity DPPA. Characterization techniques, including nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography, are used to confirm the structure and purity of the final product.

The development of new applications for 2-(Diphenylphosphino)benzoic acid continues to be an area of active research. Researchers are exploring its use in other catalytic processes, such as asymmetric olefin metathesis and C-H activation reactions. Additionally, the compound's unique properties make it a candidate for use in materials science, where it can be incorporated into polymer matrices or used to modify surfaces.

In summary, 2-(Diphenylphosphino)benzoic acid is a significant compound in the field of organometallic chemistry and catalysis. Its discovery and development have provided valuable tools for asymmetric synthesis and catalytic reactions, enhancing the ability to produce chiral and complex molecules. The continued exploration of its applications highlights its importance in both academic research and industrial processes.

References

2003. Dynamic Kinetic Asymmetric Cycloadditions of Isocyanates to Vinylaziridines. Journal of the American Chemical Society, 125(36).
DOI: 10.1021/ja037450m

2018. A Chiral Secondary Amine-Amidophosphane Precatalyst for Silver-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition Reactions. Synthesis, 50(08).
DOI: 10.1055/s-0037-1609492

2019. Gold(III)/Sodium Diphenylphosphinobenzene-3-sulfonate (TPPMS) Catalyzed Dehydrative N-Benzylation of Electron-Deficient Anilines in Water. Synthesis, 51(09).
DOI: 10.1055/s-0037-1611519.