Chiral NMR shift reagents

Both these optically active betweenanenes exhibited a (—)-Cotton effect47 at 195 nm, indicating their (R)-configuration. Hydroboration-oxidation of these specimens gave the ( )-fused alcohols 106 whose respective optical purities (7.6 and 6.0%) were estimated by means of the NMR chiral shift reagent method. 

Likewise, the same BINPHAT anion acts as an efficient NMR shift reagent for quaternary ammonium cations (182-186) including the biologically active methacoline (187). Furthermore, the BINPHAT anion has been shown to be an efficient NMR chiral shift reagent for triphenylphosphonium salts containing stereogenic centres on an aliphatic side chain, e.g. (188ab) and (189). ... 

Optical rotations were measured on Optical Activity AA-1000 or polAAr 2001 polarimeters operating at 589 nm, corresponding to the sodium D line. Enantiomeric excesses were determined by 1H NMR chiral shift reagent studies using 10 equiv of (R)-(-)- or (S)-(+)-2,2,2-trifluoro-1-(9-anthryl)ethanol (Pirkle reagent). 

Fig. 2.25. NMR spectrum of 1 2 D L asparagine mixture with NMR chiral shift reagent (a) without shift reagent (b) with shift reagent. Reproduced from Org. Lett, 2, 3543 (2000), by permission of the American Chemical Society.

Pseudolipids NMR/Chiral Shift Reagents. The following observations were... 

Kabuto K, Sasaki Y. Highly consistent correlation between absolute configuration of a-amino acids and their shift induced by the NMR. chiral shift reagent propylenediamine-tetraacetatoeuropium(ni) in aqueous solution. J. Chem. Soc., Chem. Commun. 1987 670-671. 

Commercially available nmr chiral shift reagent. Gives enantiomeric excess in some Diels-Alder synths. and cyclocondensation of aldehydes with siloxydienes. Hygroscopic volatile yellow-orange solid. Insol. H.O. 

Nmr chiral shift reagent. Light-tan powder. Indefinite Mp... 

Nmr chiral shift reagent. Yellow-orange powder (pentane). Insol. H2O. Subl.Q I 250°. Hygroscopic. Indehnite Mp. 

Nmr chiral shift reagent. Light-tan powder (hexane). Mp 211.5-213.5°. [a]g 222° (c, 1.3 in CCI4). A solvated form of indefinite Mp slowly dehydrates at 105° in vacuo. Hygroscopic, volatile. 

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