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The direct transesterification of dioxaborolanes (alkane-1,2-diol based boronate esters) was explored. Using BF3·OEt2, alkane-1,2-diol based mono- and bis-boronate esters (i.e., pinacol and ethylene glycol) have been converted quantitatively to either benzene-1,2-diol or alkane-1,3-diol based boronate esters. In the case of pinacol esters, esterification is facilitated by the accompanying pinacol rearrangement, thus shifting the reaction equilibrium.

A ligand-free copper catalyzed Suzuki-Miyaura coupling of 3,5-diiodopyridine with aryl and indole boronates has been explored in good to excellent yields. In situ generation of nano-Cu2O from CuCl2 under the reaction conditions has been discovered for the first time. The generality of the reaction was further demonstrated by the arylation of 5-iodopyrimidine, iodopyridines, iodobenzenes, and diiodobenzenes and resulted in good to moderate yields. Moreover, bisindole alkaloid Scalaridine A has been successfully synthesized in 60% overall yield.

The heterogeneous palladium-catalyzed Suzuki reactions between model aryl bromides (4-bromoanisole, 4-bromoaniline, 4-amino-2-bromopyridine, and 2-bromopyridine) and phenylboronic acid have been successfully conducted in water with no added ligand at the 100 mL scale using 20-40 mmol of aryl bromide. The product yields associated with these substrates were optimized, and key reaction parameters affecting the yields were identified. The results clearly indicate that the reaction parameters necessary to achieve high yields are substrate-dependent. In addition, it is demonstrated that aqueous Suzuki reactions of substrates containing basic nitrogen centers can produce quantitative yields of desired products in the absence of added ligand.

An unprecedentedly thermo-and air-stable Pd0 complex from readily available electron-poor trifluoromethylated phosphine was serendipitously discovered. As detailed and comparative DFT calculations indicate, the stability of the complex is associated with unusually strong ligand-ligand noncovalent interactions. The unique stability and the presence of hydrophobic structural elements of the complex offer several practical advantages, which were exploited in catalytic Suzuki-Miyaura coupling reactions.

MS and 1H, 13C and 11B NMR results are presented revealing the formation of cyclic seven-membered boronate structures at trans-1,2-diol moieties of carbohydrates providing new opportunities for the activation, protection and analysis of glucopyranose-based oligomers and polymers such as cellulose or starch. 'Coordination-induced shifts' in 13C NMR spectra were identified for the esterification by boronic acids of carbohydrates, which can be applied for further studies.

(Chemical Equation Presented) An oxidation exercise: An aerobic alcohol oxidation coupled with a regioselective palladium-catalyzed reductive functionalization of styrenes and arylboronic esters has been developed (see scheme). The mechanism is thought to proceed by initial oxidation of the solvent to generate a PdII-hydride species, which subsequently reacts with the alkene and arylboronic ester to ultimately generate a new C-C bond.

A comparative study of the transesterification of five representative chiral and achiral boronic esters with various structurally modified diols was undertaken to qualitatively understand the factors influencing the relative stability of these boronic esters. Several factors such as chelation, conformation, steric bulk of the substituents, size of the heterocycle, and entropy influence the relative rate of transesterification as well as the stability of the boronic esters. Amongst these boronic esters, pinanediol phenylboronic ester was found to be the most stable boronic ester whereas DIPT boronic ester appeared to be thermodynamically the least stable one. The transesterification with sterically hindered diols was observed to be relatively slow, but afforded thermodynamically more stable boronic esters. Boronic esters derived from cis-cyclopentanediols and the bicyclo[2.2.1]heptane-exo,exo-2,3- diols are relatively more stable. This study not only presents the qualitative picture of relative stability of various boronic esters, but also provides helpful hints regarding the possible recovery of chiral auxiliaries. Many C 2-symmetric chiral auxiliaries, such as 2,3-butanediol, 2,4-pentanediol, DIPT, and cis-cyclohexane-1,2-diol, can be retrieved by simple transesterification of the corresponding boronic esters with commercial inexpensive diols, such as pinacol, 1,3-propanediol, and neopentyl glycol.

Compositions and methods of use of boron derivatives, including benzoxaboroles, benzazaboroles and benzthiaboroles, as therapeutic agents for treatment of diseases caused by fungi, yeast, bacteria or viruses are disclosed, as well as methods for synthesis of said agents and compositions thereof.

Compounds, compositions and methods are provided which are useful in the treatment of periodontal disease.

Relative rates of reaction of the achiral cyclic phenylboronic ester 2-(phenyl)-1,3,2-dioxaborolane with a wide variety of structurally modified diols, have been studied to understand the factors influencing the relative stabilities of boronic esters. It is found that the alkyl substituents on the α-carbons of diols slow down the transesterification, but produce thermodynamically more stable boronic ester. Six-membered boronic esters are thermodynamically more stable than their corresponding five-membered analogs. Amongst cyclic 1,2-diols, cis-1,2-cyclopentanediol displaces ethylene glycol instantaneously whereas trans-1,2-cyclopentanediol is totally unreactive, which suggests that the cis-stereochemistry of the 1,2-diol is a prerequisite for transesterification. Among the 1,5-diols, diethanolamine displaces ethylene glycol quite rapidly forming a more stable bicyclic chelate in which nitrogen is attached to boron by a coordinating bond (as evident by 11B NMR spectroscopy). The oxygen atom of di(ethylene glycol) and the sulfur atom of 2,2′-thiodiethanol do not assist in displacing the ethylene glycol from their boronic esters.

The use of chiral secondary amines containing only one branched substituent has been shown to give optimal yields and stereoselectivities in the preparation of α-amino acids using the Petasis reaction. While the use of chiral primary amines generally give

A structure-activity relationship investigation for a more efficacious therapy to treat onychomycosis, a fungal infection of the toe and fingernails, led to the discovery of a boron-containing small molecule, 5-fluoro-1,3-dihydro- 1-hydroxy-2,1-benzoxaborole (AN2690), which is currently in clinical trials for onychomycosis topical treatment.

As bacteria continue to develop resistance toward current antibiotics, we find ourselves in a continual battle to identify new antibacterial agents and targets. We report herein a class of boron-containing compounds termed borinic esters that have broad spectrum antibacterial activity with minimum inhibitory concentrations (MIC) in the low microgram/mL range. These compounds were identified by screening for inhibitors against Caulobacter crescentus CcrM, an essential DNA methyltransferase from Gram negative α-proteobacteria. In addition, we demonstrate that borinic esters inhibit menaquinone methyltransferase in Gram positive bacteria using a new biochemical assay for MenH from Bacillus subtilis. Our data demonstrate the potential for further development of borinic esters as antibacterial agents as well as leads to explore more specific inhibitors against two essential bacterial enzymes.

Acyclic and cyclic esters, as well as anhydride (boroxine) of phenylboronic acids are efficient phenylating agents in copper promoted C-N and C-O bond cross-coupling reactions. The first successful C-N cross-coupling of a heterocyclic boronate with heteroarenes, such as indazole, has been demonstrated.

An efficient one-pot synthetic protocol for the synthesis of arylboronic esters has been established. The concentrated addition mixture of trimethylborate with aryl Grignard reagents was treated with low molecular weight diols (ethylene glycol, 1,3-propandiol) and toluene, the corresponding arylboronic esters were isolated in a convenient way with high yields. The diols not only serve as water replacement for the workup step, but also as well as the reagent for the preparation of arylboronic esters.

Substituted benzeneboronic acids are important intermediates in the synthesis of support matrices for affinity chromatography but their analysis by mass spectrometry is hindered by thermal reactions in the ion source.A simple derivatization with 1,2- or 1

1. A new method was proposed for the analysis of small quantities of C2-C4-diols, formed in the cleavage of lipids, based on combined gas-chromatography and mass spectrography of their phenylborate esters. 2. Phenylborate esters of d