2-Biphenylboronic acid
[CAS# 4688-76-0]

Identification

• Classification: Chemical reagent >> Organic reagent >> Aromatic hydrocarbon reagent
• Name: 2-Biphenylboronic acid
• Synonyms: (2-Phenylphenyl)boranediol; 1,1'-Biphenyl-2-boronic acid
• Molecular Formula: C₁₂H₁₁BO₂
• Molecular Weight: 198.03
• CAS Registry Number: 4688-76-0
• EC Number: 670-315-1
• SMILES: B(C1=CC=CC=C1C2=CC=CC=C2)(O)O

Properties

• Density: 1.18
• Melting point: 167-172 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H317-H319-H335
• Safety Statements: P261-P264-P264+P265-P270-P271-P272-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P319-P321-P330-P332+P317-P333+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H302
Skin sensitization	Skin Sens.	1	H317
Eye irritation	Eye Irrit.	2A	H319

Discovery and Applications

2-Biphenylboronic acid is an organoboron compound characterized by a biphenyl structure where a boronic acid functional group is attached to the second position of one of the phenyl rings. This structural arrangement imparts unique reactivity to the molecule, making it highly valuable in various fields, particularly in organic synthesis and medicinal chemistry.

The discovery of 2-biphenylboronic acid is closely linked to the development of boronic acids, a class of compounds that gained significant attention due to their versatility in chemical reactions. Boronic acids, including 2-biphenylboronic acid, have the general formula R-B(OH)₂, where R is an organic group. The presence of the boronic acid group allows these compounds to participate in various reactions, most notably the Suzuki-Miyaura coupling reaction. This reaction, which involves the coupling of an aryl or vinyl boronic acid with a halide in the presence of a palladium catalyst, has become a cornerstone of modern organic synthesis.

The application of 2-biphenylboronic acid is most prominent in the synthesis of biaryl compounds, which are ubiquitous in pharmaceuticals, agrochemicals, and materials science. The Suzuki-Miyaura coupling reaction enables the formation of carbon-carbon bonds between two aromatic rings, allowing for the efficient synthesis of biphenyl derivatives. The biphenyl moiety is a common structural motif in many biologically active molecules, making 2-biphenylboronic acid an important intermediate in the pharmaceutical industry. For example, it is used in the synthesis of kinase inhibitors, which are crucial in the treatment of cancer and other diseases.

In addition to its role in pharmaceutical synthesis, 2-biphenylboronic acid is also utilized in the development of advanced materials. Its ability to form strong carbon-carbon bonds makes it a valuable building block in the creation of polymers, liquid crystals, and organic semiconductors. These materials are essential in the production of electronic devices, such as light-emitting diodes (LEDs) and organic photovoltaics (OPVs). The biphenyl structure provides rigidity and stability, while the boronic acid group offers versatility in chemical modifications, allowing for the fine-tuning of material properties.

The chemical reactivity of 2-biphenylboronic acid extends beyond the Suzuki-Miyaura coupling reaction. It can also participate in other transformations, such as the formation of boronate esters, which are useful intermediates in various organic reactions. These esters can undergo further functionalization, leading to the synthesis of complex organic molecules with diverse applications.

Moreover, 2-biphenylboronic acid has been explored for its potential in biological applications. Boronic acids are known for their ability to form reversible covalent bonds with diols, making them useful in the development of sensors and diagnostic tools. The biphenylboronic acid derivatives can be designed to interact with specific biomolecules, enabling their use in the detection and quantification of sugars, nucleotides, and other biologically relevant compounds.

As research continues to advance, 2-biphenylboronic acid remains a compound of significant interest in both academic and industrial settings. Its role in the synthesis of complex organic molecules, coupled with its versatility in various chemical reactions, ensures its continued importance in the development of new materials, pharmaceuticals, and diagnostic tools. The ongoing exploration of its reactivity and applications will likely lead to further innovations in chemistry and related fields.

References

2022. Theoretical investigation of the mechanism of Rh(III)-catalyzed annulation of 2-biphenylboronic acid with activated alkene. Chemical Research in Chinese Universities, 38.
DOI: 10.1007/s40242-022-2187-6

2023. Palladium(II) pincer-type complexes catalyze Suzuki-Miyaura cross-coupling of 3-bromochromone and arylboronic acids via C-Br activation. Catalysis Letters, 153.
DOI: 10.1007/s10562-023-04276-4

2014. First identification of boronic species as novel potential inhibitors of the Staphylococcus aureus NorA efflux pump. Journal of Medicinal Chemistry, 57.
DOI: 10.1021/jm401808n