Página Inicial CNEA Laboratorio TANDAR Página Inicial TANDAR Historia del acelerador TANDAR Web interno Web mail
Inicio » Actividades I+D > Publicaciones 2001 > Methyl, ethyl, isopropyl and tert-butyl ...
artículo con referato
"Methyl, ethyl, isopropyl and tert-butyl 3-oxo-2-(triphenylphosphoranylidene)butyrates, a common pattern for a preferred conformation"
F. Castañeda, C.A. Terraza, M.T. Garland, C.A. Bunton and R.F. Baggio
Acta Cryst. C 57(2) (2001) 180-184
The crystal structures of four alkyl 3-oxo-2-(triphenylphosphoranylidene)butyrates, where the alkyl group is methyl (C23H21O3P·0.5C6H6), (II), ethyl (C24H23O3P), (III), isopropyl (C25H25O3P), (IV), or tert-butyl (C26H27O3P), (V), show all of them to have the same conformation. They present a tetrahedral P atom and an sp2 ylidic C atom, with the carbonyl groups adopting anti conformations with respect to the keto groups located close to the P atom. P–C–C–O torsion angles, bond lengths and angles indicate an effective electronic delocalization toward the keto groups. In each case, one H atom of the alkoxy group is close to one of the phenyl rings. These preferred conformations are evaluated as the result of attractive and repulsive intramolecular interactions.
Av. Gral Paz y Constituyentes, San Martín, Pcia. de Buenos Aires, Argentina
Tel: (54-11) 6772-7007 - Fax: (54-11) 6772-7121