Étude conformationnelle et structurale de 1,5-diacétoxy-3,4-bis(bicyclophosphoranylato)quinate de méthyle

Abstract

In connection with our work on quinic acid derivatives, which are supposed to regulate the biosynthesis of aromatic amino acids, we have prepared the methyl 1,5-di-O-acetyl-3,4-bis-O-(bicyclophosphoranylato)quinate 7. The compound obtained has been characterized by NMR (1H and 31P), IR, elemental analysis, and mass spectrometry. Its molecular structure has been determined by X-ray diffraction and an exhaustive conformational study has been accomplished. The quinic ring adopts an almost perfect chair form. Both bicyclophosphoranyl groups present a trigonal bipyramidal geometry with an axial–equatorial–axial type annelation. The pentagonal rings adopt an envelope form in which the tetrasubstituted carbon atom is at the top of the fold. Key words: shikimic acid pathway, methyl 1,5-di-O-acetyl-3,4-bis-O-(bicyclophosphoranylato)quinate, conformational analysis, 1H and 31PNMR, crystal structure.

Macrocycles containing bicyclophosphorane moieties [1]

“…Comparatively, the P-P lengths are 7.89 A in 14 and 6.48 A in 15. Such observations have been made previously with two compounds investigated in our laboratory [23,24]. They illustrate the new concept of hydrogen bonding irivolving hydrogen atoms linked to a carbon atom [25].…”

“…The bicyclophosphorane moiety adopts a nearly perfect trigonal bipyramidal geometry (Table 6) with an axial-equatorial-axial annelation, as was the case with compound D [231. Table 8 shows that, as observed in compound D [23], the five-membered rings of both compounds adopt an envelop conformation, the C( 1) and C(4) carbon atoms being at the ends of the folds which are inversely oriented with respect to the apical plane. 4.…”

SYNTHESE, STRUCTURE ET REACTIVITE D'ORGANYLOXY BICYCLOPHOSPHORANES A LIAISON P[sbnd]H

“…8 La forme enveloppe a ktt confirmke par la structure molkculaire de 17, determinee par diffraction des rayons X. 17 Nous en concluons que c' est la forme adoptee par ces cycles quel que soit le reste R (R, H ou OR) directement lie P. (p1-08).…”

Phosphoranes et thio-oxazaphospholidines d'aldohexoses protégés. Synthèses et études stéréochimiques

“…Cet handicap est en partie lev6 par la connaissance de la conformation des cycles pentagonaux qui nous est fournie par les rayons X de 12 : c'est une forrne enveloppe avec l'atorne de carbone en a de l'oxygkne a la pointe du rabat (7 …”