Rapid Proton Transfer as Cause of an Unusually Large Neighboring Group Effect

Abstract

An acceleration of the transesterification of arylboronates by a factor of about 109 can be achieved by introduction of nitrogen‐containing substituents or moieties into phenylboronic acid esters. Examples are aryl  o‐(dimethylaminomethyl)phenyl, o‐(dimethylamino)phenyl, 8‐quinolyl. Arylboronic acids thus become available which are suitable, after immobilization, for a very rapid chromatographic separation of diols.

Inhibition of Quorum Sensing in Vibrio harveyi by Boronic Acids

“…The B‐O bond is known to be strong (44). It has been reported that appropriately positioned oxygen or nitrogen can donate their lone‐pair electrons to the boron open shell and thus lower the boron p K a and convert the boron atom to its tetrahedral form (45–49). Therefore, these two compounds probably can exist in the ionized form with a formal negative charge on the boron atom at neutral pH (Figure 3, 6a and 8a ).…”

Carbohydrate recognition by boronolectins, small molecules, and lectins

“…There have also been excellent reviews on boronic acid reporters that change fluorescent properties upon binding156,188 and a review on using boronic acid in biological applications with an emphasis on inhibition of hydrolytic enzymes 151. In addition, B-N bond formation, when positioned in a relative 1,5 relationship, occupies a special place in the boronic acid-based sensor field because of the work of Wulff204,205 and Shinkai,184 and has been used as a way to modulate boronic acid fluorescence. The Wang lab has studied in detail how the B-N interactions could change its nature depending on carbohydrate complexation 206,207.…”

Molecular architecture and therapeutic potential of lectin mimics

“…One of the most promising strategies is the introduction of dialkylaminomethyl groups to the ortho position of arylboronic acids (Scheme 2). 23,24 The covalently appended amino groups facilitate formation of a boronic ester and accelerate arylboronic acid/diol association by direct B-N coordination or "solvent-insertion" mechanism. Recent investigations by X-ray crystallography, 11 B-NMR, and computational analysis support that the latter mechanism is predominant in protic solvents.…”

“…Kisher's group has also developed a second generation of the benzoboroxolefunctionalized polymer, with 10 mol% of 2-acrylamido-2-methylpropanesulfonic acid (24). 75 Incorporation of the negatively charged sulfonate groups was expected not only to increase the aqueous solubility of the polymer at neutral pH but also to increase the binding affinity to gp120 through electrostatic interaction with the positively charged peptide fragments in the V3 loop of gp120.…”