Static and dynamic stereochem. of HP(O)ButAr (Ar = 2-methyl-1-naphthyl) was studied by a combination of variable-temp. NMR (1H and 13 P), HPLC, and CD measurements as well as by MM calcns. Two unequally populated stereolabile isomers for each configurational enantiomer were detected and their anticlinal and synclinal structures assigned. All of the four species were phys. sepd. and identified on a cryogenic HPLC enantioselective column at -83 °C. The interconversion barrier measured by dynamic NMR yields essentially the same value as that measured by dynamic HPLC (14.75 and 14.95 kcal mol-1, resp.).
Conformational studies by Dynamic NMR. 75. Comparison of dynamic HPLC and dynamic NMR in the study of conformational stereodynamics: the case of the enantiomers of a hindered secondary phosphine oxide / Gasparrini, Francesco; L., Lunazzi; A., Mazzanti; Pierini, Marco; K. M., Pietrusiewicz; Villani, Claudio. - In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - ISSN 0002-7863. - STAMPA. - 122:(2000), pp. 4776-4780. [10.1021/ja9941779]
Conformational studies by Dynamic NMR. 75. Comparison of dynamic HPLC and dynamic NMR in the study of conformational stereodynamics: the case of the enantiomers of a hindered secondary phosphine oxide
GASPARRINI, Francesco;PIERINI, MARCO;VILLANI, Claudio
2000
Abstract
Static and dynamic stereochem. of HP(O)ButAr (Ar = 2-methyl-1-naphthyl) was studied by a combination of variable-temp. NMR (1H and 13 P), HPLC, and CD measurements as well as by MM calcns. Two unequally populated stereolabile isomers for each configurational enantiomer were detected and their anticlinal and synclinal structures assigned. All of the four species were phys. sepd. and identified on a cryogenic HPLC enantioselective column at -83 °C. The interconversion barrier measured by dynamic NMR yields essentially the same value as that measured by dynamic HPLC (14.75 and 14.95 kcal mol-1, resp.).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
