J. F. Brazier
Paul Sabatier University
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Featured researches published by J. F. Brazier.
Phosphorus Sulfur and Silicon and The Related Elements | 1981
M. R. Marre; J. F. Brazier; R. Wolf; A. Klaebe
Abstract It is shown that the synthesis of the optically active spirophosphorane 5 is enantiospecific. The structure and the configuration of the enantiomeric pure diastereoisomer, given by the reaction, has been established by X-rays diffraction. A mechanism accounting for the stereospecificity is proposed. The same selectivity has been observed for three other compounds.
Phosphorus Sulfur and Silicon and The Related Elements | 1985
Ousmane Diallo; J. F. Brazier; A. Klaebe; Robert Wolf
Abstract The addition of tertiary butanol on a bicycloamidophosphite is stereospecific and leads to a bicyclophosphorane according to a second order kinetic. The activation parameters and isotopic effect were determined. These results suggest the formation of a phosphonium intermediate followed by an attack by the alcoolate anion, in agreement with the stereochemistry of the reaction.
Phosphorus Sulfur and Silicon and The Related Elements | 1983
Michel Sanchez; M. R. Marre; J. F. Brazier; J. Bellan Et; Robert Wolf
Abstract The novel iminophosphenium, [(CH3)2N]2 P+=NC6H5, has been prepared by a modified Staudinger reaction. The mechanism of this process is discussed on the basis of spectroscopic studies of various derivatives of this ion.
Phosphorus Sulfur and Silicon and The Related Elements | 1977
A. Klaebe; Antonio Cachapuz Carrelhas; J. F. Brazier; Douraid Houalla; Robert Wolf
Abstract The purpose of this paper is to show that optical rotation is a convenient method for studying the intramolecular stereolability in pentacoordinated species, particularly phosphorus derivatives. In chemistry, it is difficult to present a completely new idea and we will deal with this topic under several headings.
Journal of The Chemical Society, Chemical Communications | 1976
Michael Sanchez; J. F. Brazier; Douraid Houalla; Aurelio Munoz; Robert Wolf
The reaction of phenyl azide with a PIII⇌ PV tautomeric equilibrium mixture leads to new spirophosphoranes derivatives (3a–d) bearing an exocyclic –NH·Ph group.
Journal of The Chemical Society-perkin Transactions 1 | 1974
A. Klaebe; Antonio F. C. Cachapuz; J. F. Brazier; Robert Wolf
The diastereoisomeric spirophosphoranes (1M) and (1P) possess two elements of chirality, an optically active ligand derived from (+)-pseudoephedrine and the (±)-phosphavspironone system. The rates of epimerization of these compounds were obtained from a pure diastereoisomer [very likely (1M)] isolated by crystallization using the polarimetric kinetic method. Activation parameters at 278 K are: for (1M)→(1P);ΔG1‡= 21·44 kcal mol–1, ΔH1‡= 19·8 kcal mol–1, ΔS1‡=–5·7 cal K–1; for (1P)→(1M)ΔG–1‡= 21·10 kcal mol–1, ΔH–1‡= 19·4 kcal mol–1, ΔS–1‡=–5·9 cal K–1 mol–1. These results, compared with those obtained previously for (2M)→(2P), show that the change in the rate constant of epimerization can be large (133:1) even though the atoms surrounding phosphorus are the same. Comments on the possible structure of the transition state are presented.
Tetrahedron | 1982
A. Klaebe; J. F. Brazier; A.Cachapuz Carrelhas; Bernard Garrigues; M. R. Marre; R. Contreras
Phosphorus Sulfur and Silicon and The Related Elements | 1979
C. Bonningue; J. F. Brazier; D. Houalla; F. H. Osman
Tetrahedron Letters | 1972
D. Houalla; J. F. Brazier; Michel Sanchez; Robert Wolf
Tetrahedron Letters | 1974
A. Klaebe; Antonio Cachapuz Carrelhas; J. F. Brazier; M. R. Marre; Robert Wolf