Benzene boronic acid

Structural formula
General
Surname	Benzene boronic acid
other names	Dihydroxy (phenyl) borane; Phenylboronic acid;
Molecular formula	C 6 H 7 BO 2
Brief description	colorless to yellowish odorless solid
External identifiers / databases
EC number	202-701-9
ECHA InfoCard	100.002.456
PubChem	66827
ChemSpider	60191
DrugBank	DB01795
Wikidata	Q408739
properties
Molar mass	121.93 g mol −1
Physical state	firmly
Melting point	217–220 ° C (anhydrate)
pK s value	8.83
solubility	soluble in water (10 g l −1 at 20 ° C)
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 302
	P: no P-phrases
Toxicological data	740 mg kg −1 ( LD 50 , rat , oral )
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Benzene boronic acid , also known as phenyl boronic acid , is a chemical compound from the group of organoboronic acids .

Extraction and presentation

There are numerous methods to synthesize benzene boronic acid. A common synthesis uses phenylmagnesium bromide and trimethyl borate to form the corresponding ester , which is then converted to phenylboronic acid by hydrolysis .

PhMgBr + B (OMe) ₃ → PhB (OMe) ₂ + MeOMgBr

PhB (OMe) ₂ + H ₂ O → PhB (OH) ₂ + MeOH

An analogous synthesis can also be carried out starting from phenyllithium .

PhLi + B (OMe) ₃ → PhB (OMe) ₂ + MeOLi

PhB (OMe) ₂ + H ₂ O → PhB (OH) ₂ + MeOH

properties

Benzene boronic acid is a colorless to yellowish odorless solid. The solid forms an orthorhombic crystal lattice with space group Iba 2 (space group no. 45) . Dimers are present in the solid. The compound can be trimerized to the anhydrate triphenylboroxine by means of dry heating with elimination of water . The reaction proceeds endothermically from the solid phase with a heat of reaction of 41 kJ mol ⁻¹ . Template: room group / 45

use

Benzene boronic acid is used in numerous cross-coupling reactions. In 1979 Miyarura and Suzuki found a carbon-carbon bond formation reaction (now known as Suzuki coupling ) which convert aryl boronic acids with halogenated aromatics using palladium-phosphine complexes to form biphenyl derivatives or vinyl aromatics.

Individual evidence

↑ ^a ^b ^c ^d ^e data sheet Phenylboronic acid, purum, 97.0% (HPLC) from Sigma-Aldrich , accessed on May 19, 2017 ( PDF ).
↑ ^a ^b ^c data sheet benzene boronic acid (PDF) from Merck , accessed on August 13, 2011.
↑ Entry on phenylboronic acid. In: Römpp Online . Georg Thieme Verlag, accessed on April 17, 2014.
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Dissociation Constants of Organic Acids and Bases, pp. 8-45.
^ ^A ^b Robert M. Washburn, Ernest Levens, Charles F. Albright, Franklin A. Cheap: Benzeneboronic Anhydride In: Organic Syntheses . 39, 1959, p. 3, doi : 10.15227 / orgsyn.039.0003 ; Coll. Vol. 4, 1963, p. 68 ( PDF ).
↑ Cundy, DJ; Forsyth, SA: Cupric acetate mediated N-arylation by arylboronic acids: A preliminary investigation into the scope of application in Tetrahedron Letters 39 (1998) 7979-7982, doi : 10.1016 / S0040-4039 (98) 01735-3 .
↑ ^a ^b Rettig, SJ; Trotter, J .: Crystal and molecular structure of phenylboronic acid, C ₆ H ₅ B (OH) ₂ in Can. J. Chem. 55 (1977) 3071-3075, doi : 10.1139 / v77-430 , pdf .
↑ ^a ^b Finch, A .; Gardner, PJ: Thermochemistry of phenylboronic acid, diphenylborinic acid, and their anhydrides in Trans. Faraday Soc. 62 (1966) 3314-3318, doi : 10.1039 / TF9666203314 .
↑ Miyaura, N .; Suzuki, A .: Stereoselective synthesis of arylated (E) -alkenes by the reaction of alk-1-enylboranes with aryl halides in the presence of palladium catalyst . In: J. Chem. Soc., Chem. Commun. . No. 19, 1979, p. 866. doi : 10.1039 / C39790000866 .

[Sigma-1] ↑ ^a ^b ^c ^d ^e data sheet Phenylboronic acid, purum, 97.0% (HPLC) from Sigma-Aldrich , accessed on May 19, 2017 ( PDF ).

[Merck-2] ta sheet benzene boronic acid (PDF) from Merck , accessed on August 13, 2011.

[3] Entry on phenylboronic acid. In: Römpp Online . Georg Thieme Verlag, accessed on April 17, 2014.

[CRC90_8_45-4] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Dissociation Constants of Organic Acids and Bases, pp. 8-45.

[Washburn-5] A ^b Robert M. Washburn, Ernest Levens, Charles F. Albright, Franklin A. Cheap: Benzeneboronic Anhydride In: Organic Syntheses . 39, 1959, p. 3, doi : 10.15227 / orgsyn.039.0003 ; Coll. Vol. 4, 1963, p. 68 ( PDF ).

[6] Cundy, DJ; Forsyth, SA: Cupric acetate mediated N-arylation by arylboronic acids: A preliminary investigation into the scope of application in Tetrahedron Letters 39 (1998) 7979-7982, doi : 10.1016 / S0040-4039 (98) 01735-3 .

[Rettig-7] Rettig, SJ; Trotter, J .: Crystal and molecular structure of phenylboronic acid, C ₆ H ₅ B (OH) ₂ in Can. J. Chem. 55 (1977) 3071-3075, doi : 10.1139 / v77-430 , pdf .

[Finch-8] Finch, A .; Gardner, PJ: Thermochemistry of phenylboronic acid, diphenylborinic acid, and their anhydrides in Trans. Faraday Soc. 62 (1966) 3314-3318, doi : 10.1039 / TF9666203314 .

[9] Miyaura, N .; Suzuki, A .: Stereoselective synthesis of arylated (E) -alkenes by the reaction of alk-1-enylboranes with aryl halides in the presence of palladium catalyst . In: J. Chem. Soc., Chem. Commun. . No. 19, 1979, p. 866. doi : 10.1039 / C39790000866 .