Design of Selenium-Based Chiral Chemical Probes for Simultaneous Enantio- and Chemosensing of Chiral Carboxylic Acids with Remote Stereogenic Centers by NMR Spectroscopy.

Abstract

Selenium-based enantiopure chiral chemical probes have been designed in a modular way starting from available amino alcohols. The probes developed were found to be efficient in chemoselective interaction with carboxylic functions of chiral substrates leading to diastereomeric amide formation and in sensing α-, β-, and remote (up to seven bonds away from the carboxylic group) chiral centers by using 77 Se NMR spectroscopy. As a result, it was possible to determine the enantiomeric ratio of structurally diverse individual chiral acids including polyfunctional compounds and drugs with high accuracy. An approach to analyzing the crude reaction mixtures has been successfully developed by using bifunctional selenium- and fluorine-containing chiral probes. More importantly, it was revealed that, based on the 77 Se NMR data obtained, it is possible to obtain primary information about the location and nature of the substituents at the chiral center (chemo- and enantiosensing), which can simplify the structural elucidation of complex compounds. The derivatization procedure takes as little as 5 min and can be performed directly in an NMR tube followed by NMR measurements without any isolation and purification steps.