A Common Conformation of Stabilized Triphenyl Phosphonium Ylidic Diesters with Bulky Alkoxy Groups

Castañeda F.; Silva P.; Garland, MT; Shirazi, A; Bunton, CA

Abstract

The phosphonium ylidic diesters, methyl and ethyl isopropyl and, methyl and ethyl t-butyl triphenylphosphoranylidene malonates, 1a,b and 2a,b, respectively, have the syn-anti conformation in solution, as in the crystal, and the bulkier alkoxy group is oriented towards phosphorus. The 1H NMR spectra show that in 1a,b, the isopropyl group is oriented towards the face of a phenyl group, consistent with shielding in the 1H signals, and examination of the 1H coupled 13C NMR spectra allows assignment of the acyl carbon signals. Computed bond lengths and angles for isolated molecules are similar to those in the crystal, and the geometry and the NMR spectra indicate extensive ylidic resonance. Estimated partial atomic charges on the ester oxygens are more negative when they are oriented towards, rather than away from, phosphorus.

Más información

Título según WOS: A Common Conformation of Stabilized Triphenyl Phosphonium Ylidic Diesters with Bulky Alkoxy Groups
Título según SCOPUS: A common conformation of stabilized triphenyl phosphonium ylidic diesters with bulky alkoxy groups
Título de la Revista: PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS
Volumen: 184
Número: 8
Editorial: GORDON BREACH SCI PUBL LTD
Fecha de publicación: 2009
Página de inicio: 2152
Página final: 2168
Idioma: English
DOI:

10.1080/10426500802445373

Notas: ISI, SCOPUS