This special issue highlights research presented during the Boronic Acids Symposium held at Pacifichem 2010 in December of last year. Over 40 researchers from academia and industry presented talks and posters as part of the symposium and 11 Pacifichem participants share their work here.

The preparation of tetra-n-butylammonium spiroborates derived from aliphatic α-hydroxy acids and dicarboxylic acids is investigated. The spiroborates derived from glycolic acid and (S)-(+)-mandelic acid are the most stable and show promise as potential wood preservatives. A new oxalato triborate related in structure to borax has been prepared and characterized by X-ray crystallography.

An efficient synthesis of pinanediol (hydroxymethyl)boronate (12) from diisopropyl (bromomethyl)boronate (9) is described. The cyclic dimer 11 of (hydroxymethyl)boronic acid is stable in aqueous acid but degraded to methanol and borate by heating in base or neutral buffer over a period of several hours.

Various mono- and di-ortho-carborane-substituted 1,3,5-triazines were synthesized and tested for their ability to inhibit cell growth and the activities of topoisomerases I and II. Among the compounds synthesized, 3c, 4c, and 4f completely inhibited topoisomerase I activity without affecting topoisomerase II activity, whereas 3a and 3d completely inhibited topoisomerase II activity without affecting topoisomerase I activity, at 100 μM.

Novel highly water-soluble boronic acids with quenched fluorescence that could be revived with fructose binding are reported. The quenched fluorescence of the boronic acids sensors is empirically predicted from the kinetic and thermodynamic fluorescence quenching of the amino-fluorophore precursors with phenylboronic acid and an aliphatic imine.

The asymmetric arylation of imines with arylboronic acids was realized by using rhodium/chiral bidentate phosphoramidite ligand ((R,R)-N-Me-BIPAM). This method affords a direct access to chiral arylglycines in good yield with high enantioselectivities.

Attempts to create a self-assembling sialic acid sensor resulted in the discovery that m-aminophenyl boronic acid alone has an appreciable affinity for the target sugar.

Brønsted base-assisted boronic acid catalysis for the dehydrative self-condensation of carboxylic acids is described. Arylboronic acids bearing bulky (N,N-dialkylamino)methyl groups at the 2,6-positions can catalyse the intramolecular dehydrative condensation of di- and tetracarboxylic acids. The steric bulkiness of the (N,N-dialkylamino)methyl groups prevents the formation of less active species such as the N→B chelated species and triarylboroxines.

Reversible covalent interactions between diphenylborinic acid and diols have been studied using an indicator-displacement assay in aqueous solution. The results indicate that borinic acids, which have largely been ignored for applications in molecular recognition, display high affinity for such analytes, and a distinct selectivity pattern from that of a boronic acid of similar pK_a.

A rhodamine based boronic acid linearly responds to increasing 5-aminoimidazole-4-carboxamide riboside concentrations, a surrogate for adenylosuccinate lyase substrates involved in rare but serious inborn errors of purine metabolism which cause autistic features, mental retardation, and/or neonatal seizures. The indicator functions in both simple buffered systems and systems containing unprocessed human urine.

Organoboron compounds are extremely useful building blocks for organic synthesis; however, they suffer from incompatibilities with many synthetic transformations. A recently reported boron protecting group, the N-methyliminodiacetate (MIDA) boronate complex ,shows good stability and resistance to a wide variety of chemistries including many transition metal catalyzed reactions. The ability to protect and mask the boron functionality has led to an expanded role for boron in the synthesis of complex molecules.

To reveal the relationship between the properties and structures of the functional materials A, B, C, D, and E, (see image) theoretical calculations are carried out by density functional theory to investigate their structural and electronic properties.

Chemical structure and physical structure of starch can both be modulated to reduce the extent of starch digestion in the small intestine, allowing more of the ingested starch to reach the large intestine. Anaerobic fermentation of starch is increased, and potentially beneficial microbial by-products are absorbed from the large intestine.

Silver nanocubes were synthesized by using the polyol process but with careful control over the percentage of oxygen in the headspace above the reaction mixture. It was found that between 6.5 and 7.5 % oxygen monodisperse nanocubes of edge length 100–115 nm were produced but outside that range rods, spheres, or no particles were produced.

Flowerlike Ni microcrystals composed of star-shaped Ni nanorods were fabricated by a facile approach, which exhibited significantly enhanced coercivity compared with bulk Ni. The growth mechanism of the flowerlike architecture could be briefly elucidated as follows: the formation of cores composed of aggregated Ni nanoparticles and the anisotropic growth of the star-shaped Ni nanorods around the cores.

Compounds 1–3 were synthesized from similar reaction systems, but their structures are very different because of the different pH values. It was established that the pH of the reaction mixture and the amount of ethanediamine play very important roles in the assembly of polyoxometalate-based compounds.

A high yielding practical three-step procedure, which relies on an extractive work-up procedure, has been developed to convert N-phenylsulfonyl-trans-4-hydroxy-l-proline to N-phenylsulfonyl-cis-4-hydroxy-l-proline methyl ester in 82 % yield over three steps.

The N-demethylation of opiates is a key step in the preparation of several semi-synthetic opiate derived pharmaceuticals. Herein we report an efficient method for achieving this transformation in high yield using iron as the catalyst.

The preparation of a mesoporous silica-supported Er^III catalyst using the microwave-assisted post-calcination functionalization of Mobil Composition of Matter-41 silica as the key step is described. The required time for functionalization was reduced from several hours to 10 min using sealed-vessel microwave technology. Control experiments using conventional heating at the same temperature demonstrated that the rate increase is owing to a purely thermal/kinetic effect as a result of the higher reaction temperature. The resulting Er^III catalyst was tested for the first time as a catalyst in the continuous flow deprotection of benzaldehyde dimethylacetal.

A metal-free way for the activation of the C–O bond of ferrocenyl alcohols is accomplished in AcOH. It provides a relatively green protocol for the α-functionalization of ferrocenyl alcohols by active methylene compounds, electron-rich arenes, anilines, alcohols, and thiols.