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The versatility of the natural products (2S,3S)- and (2S,3R)-3-hydroxy-5-oxotetrahydrofuran-2,3-dicarboxylic acids (1 and 2), isolated in large amounts from tropical plant sources, has been demonstrated by the construction of 3-substituted and 3,4-disubstituted chiral pyrrolidine-2,5-diones. The absolute configurations of chiral pyrrolidine-2,5-diones have been ascertained using chiroptical spectroscopic methods and/or single-crystal XRD data. A combination of different reaction strategies delivering a diverse matrix of fused heterocyclic ring systems is presented. The pyrrolo­[2,1-a]­isoquinoline alkaloid (+)-crispine A possesses a wide range of pharmacological activities including antidepressant, antiplatelet, antileukemic, and anticancer activities. The analogues of indolizino­[8,7-b]­indole alkaloids (+)- and (−)-harmicine show strong antileishmanial, antinociceptive, PDE5-inhibitory, antimalarial, and antiviral activities. The bicyclic furo­[2,3-b]­pyrrolo skeleton is present in many natural products. Thus, the uniqueness of relatively cheap, naturally occurring chiral 2-hydroxycitric acid lactones as chirons has been demonstrated by the construction of some important molecular skeletons that are otherwise difficult to synthesize.

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Small chiral molecules are excellent candidates to push the boundaries of enantiodiscrimination analytical techniques. Here is reported the synthesis of two new deuterated chiral probes, (R)-and (S)-[ 2 H]-ethyl tosylate obtained with high ee's. Due to their crypto-optically active properties, the discrimination of each enantiomer is challenging. While their enantiopurity is determined by 2 H-NMR in chiral anisotropic media, their identification was performed by combining quantum chemical calculations and vibrational circular dichroism analysis.

The experimental vibrational circular dichroism (VCD) and electronic circular dichroism (ECD) spectra were measured for the enantiomers of [1]rotaxane 1. These experimental spectra have been analyzed using predicted VCD and ECD spectra for (S, Rmp) or (S, Smp) diastereomers using density functional theory. This comparison allowed for a definitive assignment of the absolute configuration of 1.