Effective enantiodifferentiation of spirochalcogenuranes by the dirhodium method: towards the determination of absolute configurations?
The properties of chiral spirochalcogenuranes acting as ligands in adducts with a chiral dirhodium tetracarboxylate complex is explored, and the individual adduct species are characterized by low-temperature NMR spectroscopy. Chiral recognition and the determination of enantiomeric composition of the chiral spirochalcogenuranes is easy by evaluating NMR signal dispersions both at low and at room- or slightly elevated temperatures. The uniformity in the signs of 1H dispersion effects and taking reference to the spiroselenurane with known absolute configuration [(S)-(-)-2] indicates that a convenient rule for the determination of absolute configuration in the spirochalcogenurane system can be established on the basis of 1H chemical shift dispersions.
Gáti
Tamás
T
Institute for General and Analytical Chemistry of the Budapest University of Technology and Economics, Budapest, Hungary.
Tóth
Gábor
G
Drabowicz
Józef
J
Moeller
Stefan
S
Hofer
Edgar
E
Polavarapu
Prasad
P
Duddeck
Helmut
H