Comparison of dynamic HPLC and dynamic NMR in the study of conformational stereodynamics: Case of the enantiomers of a hindered secondary phosphine oxide

Journal of the American Chemical Society

Volumn 122, Issue 19, 2000, Pages 4776-4780

  Gasparrini, F ^a   Lunazzi, L ^b   Mazzanti, A ^b   Pierini, M ^d   Pietrusiewicz, K M ^c   Villani, C ^d  

^a SAPIENZA UNIVERSITY OF ROME   (Italy)

^b UNIVERSITY OF BOLOGNA   (Italy)

^c MARIA CURIE SK ODOWSKA UNIVERSITY   (Poland)

^d UNIVERSITY OF CHIETI   (Italy)

Author keywords

[No Author keywords available]

Indexed keywords

PHOSPHINE OXIDE DERIVATIVE;

ARTICLE; CARBON NUCLEAR MAGNETIC RESONANCE; CHEMICAL STRUCTURE; CIRCULAR DICHROISM; ENANTIOMER; HIGH PERFORMANCE LIQUID CHROMATOGRAPHY; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; PROTON NUCLEAR MAGNETIC RESONANCE; STEREOCHEMISTRY;

EID: 0034679101     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja9941779     Document Type: Article

References (15)

1. Conformational Studies by Dynamic NMR. 75. For part 74, see: Lunazzi, L.; Mazzanti, A.; Muñoz Alvarez, A. J. Org. Chem. 2000, 65, in press (Web release date: April 14, 2000).
2. (a) Gasparrini, F. Lunazzi, L.; Misiti, D.; Villani, C. Acc. Chem. Res. 1995, 28, 163 and references quoted therein.
3. (b) Casarini, D.; Foresti, E.; Gasparrini, F.; Lunazzi, L.; Macciantelli, D.; Misiti, D.; Villani, C. J. Org. Chem. 1993, 58, 5674.
4. (c) Casarini, D.; Lunazzi, L.; Gasparrini, F.; Villani, C.; Cirilli, M.; Gavuzzo, E. J. Org. Chem. 1995, 60, 97.
5. A small negative NOE effect is observed for the doublet of the major conformer at 7.95 ppm in Figure 1. This signal corresponds to that of the hydrogen in position 4 of the naphthalene ring, and its small negative NOE is a consequence of the large positive NOE experienced by the nearby hydrogen in position 3. This indirect negative NOE is known to occur quite often when two hydrogens are in a ortho relationship (see: Kruse, L. I.; DeBrosse, C. W.; Kruse, C. H. J. Am. Chem. Soc. 1985, 107, 5435).
6. As the MM-computed dihedral angle C-8a,C-1,P,O in Chart 1 has a value (56°) exceeding 30°, the term synclinal (sc) has been preferred to the term synperiplanar (suggested by: Baker, R. W.; Kyasnor, R. V.; Sargent, M. V. J. Chem. Soc:, Perkin Trans 2 1998, 1333) for the more stable conformer. Likewise the term anticlinal (ac) has been preferred to antiperiplanar for the less stable conformer, since the corresponding angle (146°) is less than 150°.
7. Computer package PC Model 4.0, Serena Software, Bloomington, IN.
8. On the basis of these distances, the NOE expected to occur in the less stable ac rotamer should be 22 times smaller than that determined in the sc rotamer, i.e. 0.11/22 = 0.005. A NOE value of 0.5% is too small to be observed in our experimental conditions.
9. Eliel, E. L.; Wilen, S. H. Stereochemistry of Organic Compounds; J. Wiley: New York, 1994; p 55.
10. Jung, M. QCPE Bull. 1992, 12, 52.
11. Gasparrini, F.; Misiti, D.; Pierini, M.; Villani, C. Tetrahedron: Asymmetry 1997, 8, 2069.
12. (a) Gargaro, G.; Gasparrini, F.; Misiti, D.; Natile, G.; Palmieri, G. Chromatographia 1987, 24, 505.
13. (b) Gasparrini, F.; Misiti, D.; Villani, C. Chirality 1992, 4, 447.
14. (c) Gasparrini, F.; Misiti, D.; Villani, C. J. Cromatogr. A 1995, 694, 163.
15. QCPE program No. 633, Indiana University, Bloomington, IN.