A practically simple three-component chiral derivatization protocol for determining the enantiopurity of chiral hydroxylamines by (1)H NMR spectroscopic analysis is described, involving their treatment with 2-formylphenylboronic acid and enantiopure BINOL to afford a mixture of diastereomeric nitrono-boronate esters whose ratio is an accurate reflection of the enantiopurity of the parent hydroxylamine.

A practically simple three-component Strecker reaction for the asymmetric synthesis of enantiopure α-arylglycines has been developed. Addition of a range of aryl-aldehydes to a solution of sodium cyanide and (S)-1-(4-methoxyphenyl)ethylamine affords highly crystalline (S,S)-α-aminonitriles that are easily obtained in diastereomerically pure form. Heating the resultant (S,S)-α-aminonitriles in 6 M aqueous HCl at reflux resulted in cleavage of their chiral auxiliary fragments and concomitant hydrolysis of their nitrile groups to afford enantiopure (S)-α-arylglycines. The enantiopurities of these (S)-α-arylglycines were determined via derivatization of their corresponding methyl esters with 2-formylphenylboronic acid and (S)-BINOL, followed by (1)H NMR spectroscopic analysis of the resultant mixtures of diastereomeric iminoboronate esters.

An electrolyte-stable polymer composite sensor film based on 2.4% boronic acid substituted polyacrylamide (poly[acrylamide-co-3-(methacrylamido)-phenylboronic acid] or P(A-MPBA)) and polydiallyl-dimethyl-ammonium chloride (or PDDACl) is obtained in a coil-by-coil deposition procedure. Based on AFM evidence, the resulting coil aggregate deposits show ca. 5-10 nm diameter and the average film thickness increases with ca. 1 nm per deposition cycle consistent approximately with the solution coil diameter. In electrochemical experiments alizarin red S is employed as a boronic acid indicating redox probe with a Langmuirian binding constant of ca. K ¼ 4 Â 10 6 M À1 and two distinct redox responses tentatively assigned here to two isomeric forms of the complex in oxidized and reduced state. Inter-and intra-coil electron transfer and electron hopping occurs during alizarin red S reduction and back-oxidation. Both smooth and mesoporous ITO substrates are employed.

A practically simple derivatization protocol for determining the enantiopurity of chiral diols by (1)H NMR spectroscopic analysis is described. Diols were treated with 0.5 equiv of 1,3-phenyldiboronic acid to afford mixtures of diastereomeric boronate esters whose homochiral/heterochiral ratios are an accurate reflection of the diol's enantiopurity.

TAYLOR, J. E.; TICKELL, D. A.; MAHON, M. F.; BULL*, S. D.; JAMES, T. D.; J. Org. Chem. 76 (2011) 15, 6038-6047, http://dx.