Determination of Enantiomeric Purity for Chiral π‐Basic Aromatic Alcohols Chiral Samples by ¹H NMR Spectroscopy

Abstract

N-3,5-Dinitrobenzoyl(DNB)-(R)-phenylglycinol (Sel 1) and its silylation product (Sel 2) were used as the HPLC chiral stationary phase (CSP) for the resolution of racemic analytes. 2,2,2-Trifluoro-1-(9-anthryl) ethanol (S1), 1,1 0 -bi-2-naphthol (S2), and 6,6 0 -dibromo-1,1 0 -bi-2-naphthol (S3) were separated on the CSP, but the enantiomeric purities could not be accurately determined because of low resolution (Rs). In this study, the enantiomeric purity of S1-S3 were determined using Sel 1, Sel 2, and 1,3-bis[(S)methylbutoxy] calix[4]arene-2,4-diol (Sel 3). These were used for 1 H NMR experiments in three different solvents (CDCl 3 , DMSO-d 6 , and acetone-d 6 ). The accuracy of the enantiomeric purity of S1-S3 with Sel 2 was more than 98% when using CDCl 3 .

Recent advances in catalytic silylation of hydroxyl‐bearing compounds: A green technique for protection of alcohols using Si–O bond formations

“…[1][2][3][4] In this sense, a wide variety of protective groups have been developed. [4][5][6][7][8] There are different requirements which must be fulfilled by a protective group [9][10][11][12][13] ; including the following: (1) In order to have a protected substrate, it must selectively react in good yield [14] ; (2) it should be selectively removed in good yield by available, nontoxic reagents by which the regenerated functional group is not attacked [15,16] ; (3) it must form a derivative being able to be separated from side products related to its formation or cleavage [17,18] ; and (4) with the aim of avoiding more sites of reaction, it must possess a minimum of additional functionality. [19] Moreover, one should pay attention to the fact that no protective group is the best protective group.…”