A bisthiourea-based 1 H NMR chiral sensor for chiral discrimination of a variety of chiral compounds

The robust, readily available cobalt(iii) trication [Co(NH2CHPhCHPhNH2)3]3+ is a progenitor of broadly applicable chirality and prochirality sensing agents

“…Most of the other CSAs described in the literature also feature hydrogen bond donor groups, 17 , 19 – 21 , 23 – 30 although many possess acceptor groups as well. 17 , 20 , 21 , 23 , 29 Typical donor groups include ureas or chalcogenoureas, 25 , 26 , 30 squaramides, 27 secondary amines, 24 amides of primary amines, 17 , 23 , 29 sulfonamides, 19 and BINOL derivatives. 20 However, many of these have only been applied to one or two functional groups.…”

“…There is a wider selection of CSAs that have been applied to four-seven functional groups. 21 , 22 , 25 , 29 These generally require loadings of 100–300 mol%, although with one analyte the CSA 49 ( Fig. 5, R = Ph ) was shown to be effective at 60 mol%.…”

“… 17 – 30 Many but not all of the CSAs are hydrogen bond donors, often with two-four NH or OH groups. 17 , 21 , 22 , 25 – 28 , 30 Some of these have been tailored to recognize a specific functional group, 19 , 23 , 24 , 26 – 28 while others have wider applicability. 17 , 20 – 22 , 25 , 29 , 30 …”

Recent Advances in Multinuclear NMR Spectroscopy for Chiral Recognition of Organic Compounds

“…However, the search for new chiral discriminating procedures that allow for quick analysis, high resolution, and utility for many non-volatile or thermally unstable compounds is increasing [ 9 , 10 , 11 , 12 ]. Among the several stereodiscrimination methods, including X-ray, circular dichroism, fluorescence spectroscopy, and electrophoresis, nuclear magnetic resonance (NMR) spectroscopy continues to be a useful tool for determining the enantiomeric purity and assigning the absolute configuration of chiral molecules [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”

Chirality Sensing of Molecules with Diverse Functional Groups by Using N‐tert‐Butyl Sulfinyl Squaramide

“…Most CSAs, however, contain a specific functional group that recognizes only one type of guest molecule, and the typical large pocket‐like chiral environment of most CSAs requires a multistep approach for their synthesis. In addition, only a limited number of CSAs, have a high enantiodiscriminating ability for various chiral compounds. Therefore, the development of a simple CSA that can discriminate between chiral compounds that contain a variety of different functional groups is highly desirable.…”