Absolute configurations of some heterocyclic acids

Abstract

Employing the method of asymmetric transformation, the absolute configurations of heterocyclic acids III, IV, Va, and VIIa have been determined. The acids Va and VIIa were chemically correlated with alcohols of known absolute configurations.

2-(Tetrahydrofuran-2-yl)acetic Acid and Ester Derivatives as Long-Range Pollinator Attractants in the Sexually Deceptive Orchid Cryptostylis ovata

“…All EIMS spectra were fundamentally different from ours, suggesting different compounds. In this study, both enantiomers of 1 were prepared from enantiopure tetrahydrofuran-2-carboxylic acid, where the absolute configuration has been assigned . NMR data of the isolated natural products, purchased rac - 1 , and the synthetically prepared products are identical and in full agreement with the most recent studies. , …”

“…In this study, both enantiomers of 1 were prepared from enantiopure tetrahydrofuran-2-carboxylic acid, where the absolute configuration has been assigned. 43 NMR data of the isolated natural products, purchased rac-1, and the synthetically prepared products are identical and in full agreement with the most recent studies. 44,45 Despite their structural simplicity, there are only a few examples of oxygenated tetrahydrofuran derivatives as floral volatiles or pheromone components.…”

“…The absolute configuration of the natural products was confirmed by preparing ( R )- 1 and ( S )- 1 from tetrahydrofuran-2-carboxylic acid − of known configuration, purchased from Enamine Ltd., Ukraine. The specific rotations of the R - and S -enantiomers of tetrahydrofuran-2-carboxylic acid, respectively were confirmed beforehand: [α] 22 D +16.0 and −15.6 (CHCl 3 ) respectively.…”

Intermolecular Association of Tetrahydrofuran-2-carboxylic Acid in Solution: A Vibrational Circular Dichroism Study

“…( R )-(+)- 1 (α D 20 = +30.0 ( c = 0.34, CHCl 3 )) 1 and ( S )-(−)- 1 (α D 20 = −12.6 ( c = 7.70, H 2 O) were obtained from Acros with a 97.5% ee and were used without further purification. IR spectra are measured with a Bruker Vector 22 FTIR spectrometer.…”

“…Combining the semiquantitative populations and DFT results, the experimental IR and VCD will be assessed. 27 were obtained from Acros with a 97.5% ee and were used without further purification. IR spectra are measured with a Bruker Vector 22 FTIR spectrometer.…”