Diarylborinic Acids Research Articles

Use of Boron Enolates in Water. The First Boron Enolate‐Mediated Diastereoselective Aldol Reactions Using Catalytic Boron Sources.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Use of boron enolates in water. The first boron enolate-mediated diastereoselective aldol reactions using catalytic boron sources

Highly diastereoselective aldol reactions in water using a catalytic amount of diarylborinic acid have been developed. The reactions proceeded smoothly in the presence of a small amount of an anionic surfactant and a Brønsted acid. Water was the most suitable solvent, and organic solvents such as ether and dichloromethane were ineffective in this system. Use of bis(4-trifluoromethylphenyl)borinic acid gave high catalytic activity. It is most plausible to conclude that the active species of the reactions are boron enolates, and this is the first example of catalytic use of a boron source in boron enolate-mediated diastereoselective aldol reactions.

ChemInform Abstract: Suzuki Reaction of a Diarylborinic Acid: One‐Pot Preparation and Cross‐Coupling of Bis(3,5‐dimethylphenyl)borinic Acid.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Suzuki Reaction of a Diarylborinic Acid: One-Pot Preparation and Cross-Coupling of Bis(3,5-dimethylphenyl)borinic Acid

3,5-Dimethylphenylmagnesium bromide reacts with triisopropyl borate to give 3,5-dimethylphenylboronic acid and bis(3,5-dimethylphenyl)borinic acid. Conditions were found which allowed the clean preparation of bis(3,5-dimethylphenyl)borinic acid, which was coupled with a vinyl triflate using Suzuki cross-coupling conditions. Both aryl groups were efficiently transferred from boron in the Suzuki step.

ChemInform Abstract: Structural Studies of Organoboron Compounds. Part 72. Nitrones and Oximes of Bifunctional Carbonyl Compounds and Their Reaction Products with Diarylborinic Acids. Crystal and Molecular Structure of Examples of Five‐, Six‐, and Seven‐membered Boron Chelates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Nitrones and oximes of bifunctional carbonyl compounds and their reaction products with diarylborinic acids. Crystal and molecular structure of examples of five-, six-, and seven-membered boron chelates

Synthesis has been carried out of diarylboron chelates of 2- and 3-hydroxynitrones, of 2- and 3-hydroxyoximes, and of 2-carboxynitrones and a 2-carboxyoxime. The structures have been determined from spectroscopic data and from X-ray analyses of 5d, 9a, 11b, and 19. Crystals (at 180 K) of 5d are monoclinic, a = 10.543(2), b = 19.085(4), c = 10.2667(3) Å, β = 90.4978(7)°, Z = 4, space group P21/c; those of 9a are orthorhombic, a = 10.9913(5), b = 14.9329(7), c = 10.2460(13) Å, Z = 4, space group P212121; those of 11b are monoclinic, a = 11.227(2), b = 9.967(2), c = 17.0537(4) Å, β = 105.4179(5)°, Z = 4, space group P21/n; those of 19 are monoclinic, a = 11.1847(15), b = 13.715(3), c = 11.5559(5) Å, β = 104.8730(10)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R(F, I [Formula: see text] 3σ(I)) = 0.049, 0.047, 0.042, and 0.047, respectively, for CCD data for 5d, 9a, 11b, and 19. The four molecules contain five-, seven-, six-, and five-membered rings, respectively, with O-B-N groups in the 5d, 11b, and 19, and O-B-O in 9a; the rings exhibit various deviations from planarity, particularly the seven-membered ring.Key words: diarylboron chelates, hydroxyoximes, hydroxynitrones, carboxyoximes, carboxynitrones, organoboron compounds, crystal structure.

Nitrones and o×imes of bifunctional carbonyl compounds and their reaction products with diarylborinic acids. Crystal and molecular structure of e×amples of five-, si×-, and seven-membered boron chelates

Nitrones and o×imes of bifunctional carbonyl compounds and their reaction products with diarylborinic acids. Crystal and molecular structure of e×amples of five-, si×-, and seven-membered boron chelates

Arylboron Compounds as Acid Catalysts in Organic Synthetic Transformations

Arylboron compounds, ArnB(OH)3–n (n = 1–3), bearing electron-withdrawing aromatic groups such as triarylboranes, diarylborinic acids, and arylboronic acids represent a new class of air-stable and water-tolerant Lewis acid or Bronsted acid catalysts in organic synthesis. In particular, while tris(pentafluorophenyl)borane has primarily been used as a co-catalyst in metallocene-mediated olefin polymerization, its potential as a Lewis acid catalyst for organic transformation is now much more extensive. Diarylborinic acids and arylboronic acids have shown themselves to be powerful tools in the design of chiral boron catalysts. This article provides a comprehensive summary of the organic transformations catalyzed by arylboron compounds as acids.

ChemInform Abstract: Diarylborinic Acids as Efficient Catalysts for Selective Dehydration of Aldols.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Diarylborinic Acids as Efficient Catalysts for Selective Dehydration of Aldols

Diarylborinic Acids as Efficient Catalysts for Selective Dehydration of Aldols

Structural studies of organoboron compounds LXI. Synthesis of (alkylideniminoxy)- diarylboranes and crystal and molecular structure of dimeric (ethylideniminoxy)-bis(4-methoxyphenyl)borane [3,3,6,6-tetrakis(4-methoxyphenyl)-2,5-diethylidene-1,4-dioxa-2,5-diazonia-3,6-diboratacyclohexane

Oxime diarylborinates, 4, were obtained from several aliphatic and aromatic aldoximes as well as from cyclic ketoximes by acylation with a diarylborinic acid or anhydride (R2B-X, R = aryl, X = OH or OBR2). Compounds 4 could also be synthesized by condensation of an (aminoxy)-diarylborane, which supposedly has a cyclodimeric BONBON structure, with an aldehyde or with a ketone. Crystals of 3,3,6,6-tetrakis(4-methoxyphenyl)-2,5-diethylidene-1,4-dioxa-2,5-diazonia-3,6-diboratacyclohexane, 4b, are monoclinic, a = 7.9182(9), b = 19.7582(9), c = 9.6779(8) Å, β = 91.598(8)°, Z = 2, space group P21/n. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R = 0.033 and Rw = 0.034 for 2344 reflections with I ≥ 3σ(F2). A dimeric structure featuring a central six-membered BONBON ring has been established for the oxime diarylborinate 4b. This represents the first structurally characterized example of a monocyclic BONBON ring.

Umsetzung von Brenzcatechinen mit diarylborinsäuren zu paramagnetischen boratkomplexen

Diaryl borinic acids react smoothly in organic solvents with catechols to stable paramaagnetic complexes. The ESR spectra of the solutions show the hydrogen HFS of the catechol and the coupling with the 11B and 10B nuclei.

Boron photochemistry III. Photolysis of some naphthalene-substituted borate complexes

The photolysis of two naphthalene-substituted “ate” complexes, lithium tetra-2-naphthylborate and lithium phenyltri-1-naphthylborate, has been carried out in the presence and absence of air. In both cases in the absence of air, the products are dihydrobiaryls, biaryls and diarylborinic acids. Air eliminates the dihydro derivatives to provide the biaryls and naphthols which result at the expense of the diarylborinic acids. The absence of biphenyl and phenylcyclohexadienes in the photolysis product of lithium phenyltri-1-naphthylborate indicates that the photolysis is intramolecular.

Chelate aus Diarylborinsäuren undβ-Ketosäureestern

Diarylborinic acids form stable chelates withβ-keto acid esters. Borinic acids, when being synthetized, can be stabilized in compounds resulting from the combination withβ-keto acid esters. The chelates so formed are suitable—like the free borinic acids or their anhydrides—for further transformation. These chelates have several advantages in comparison with those formed withβ-amino ethanol.

965. Aminoditolylborane and the preparation of diarylborinic acids

965. Aminoditolylborane and the preparation of diarylborinic acids

Organoboron compounds Communication 8. Synthesis and properties of diarylborinic acids

1. The isobutyl esters of di-1-naphthyl-, bis-p-bromophenyl-, and bis-p-chlorophenyl-borinic acids were prepared. 2. It was shown that when the isobutyl esters of di-1-naphthyl-, bis-p-bromophenyl-, and bis-p-chlorophenyl-borinic acids were treated with aqueous solutions of caustic soda, caustic potash, ammonia, and barium hydroxide, salts of the corresponding diaryldihydroxyboric acids were formed. 3. Di-1-naphthyl-, bis-p-bromophenyl, and bis-p-chlorophenyl-borinic acids were prepared by treating salts of di-1-naphthyl-, bis-p-bromophenyl-, and bis-p-chlorophenyl-dihydroxyboric acids with dilute hydrochloric acid. 4. It was shown that data reported in the literature for bis-p-bromophenyl- and bis-p-chlorophenylborinic acids are incorrect.