J. Martelli

Synthese de cyclopropanes electrophiles chiraux par l'intermediaire de complexes butadiene-fer tricarbonyle optiquement actifs.

Resume Chiral electrophilic cyclopropanes are prepared, in high enantiomeric excess (e.e > 90 %) starting from the optically active complexes 3a and 3b . A simple and efficient method. for the resolution of the key intermediate complex 1 is described.

The use of circular dichroism for the determination of the absolute configuration of chiral butadiene-tricarbonyl iron complexes

Abstract The circular dichroism spectra of functionalized butadiene-tricarbonyliron complexes can be used to predict the absolute configuration of these organometallic derivatives.

Stereoselective synthesis and Diels-Alder reactions of bis-Ether 1,3 Dienes. A further test for cooperativity during cycloaddition reactions.

A stereoselective synthesis of dienes 1a and 1b, using butadiene-iron tricarbonyl complexes, is described. Higher diastereoselectivity is observed during Diels-Alder reaction of 1a as compared with 1c, affording good evidence for cooperativity in these cycloadditions.

Diels-alder reactions on linear polyenes, selectively protected as their tricarbonyl-iron complexes.

Abstract The first examples of Diels-Alder reactions using dienophiles or a diene bearing butadienetricarbonyliron moieties are described. These highly stereoselective reactions are useful for the synthesis of polycyclic derivatives via tandem cycloadditions.

Addition d'alcoxycarbonyl-2 aziridines, ylures d'azomethine potentiels, a quelques isocyanates et isothiocyanates

Resume Addition of 2-alkoxycarbonylaziridines, which are potential azomethine ylids, with methyl and phenyl isocyanates and isothiocyanates lead to epimeric imidazolidones or thioimidazolidones resulting from the addition of the azomethine ylid to the carbon-nitrogen double bond of the dipolarophile. In all the cases only one direction of addition was observed. The structure of the resulting compounds was established by means of spectroscopic methods (IR, NMR and particularly mass spectrometry). The second order perturbation theory allows a rationalization of the results related to the site and to the orientation of the addition of the azomethine ylids to methyl and phenyl isocyanates.

Utilisation des complexes butadiène-fer tricarbonyle pour la synthèse de chlorhydrines et d'époxydes diéniques

Resume Chlorhydrins bearing a butadiene-iron tricarbonyl moiety in the α position are easily prepared. These new derivatives exhibit an unusually low reactivity. After decomplexation, chlorhydrins and epoxydienes are obtained in good yields.

Synthesis of new functionalized azadiene carbonyliron complexes

Abstract New carbonyliron complexes of 1-aza-1,3-dienes 3, 4 and 6 bearing an aldehyde function in position 4 are easily prepared from the fumaraldehyde complexes, 1 and 5, by aza Wittig reactions.

Synthesis of stable carbonyl-iron complexes of fumaraldehyde.

Abstract Stable carbonyl-iron complexes of fumaraldehyde are readily prepared in two steps from the easily accessible olefin 4 .

Modification de la selectivite dans les cycloadditions I. synthese et reactivite de complexes fer-tricarbonyle isomeres.

Resume A versatile route to triene tetrahapto iron tricarbonyl bond shift isomers 5 and 7 is described. The reaction of 5 and 7 with CH2N2 or sulfur ylid 13 gives some indications concerning the scope and limitations of this type of complex as selective protecting group : if diazomethane adds specifically on the free double bonds in 5 and 7 , a different reaction occurs with ylid 13 .

A novel preparation of electrophilic cyclopropanes

Electrophilic cyclopropanes are conveniently prepared by decomposition of the corresponding Δ1-pyrazolines in the presence of a small amount of Ce-(NH4)2(NO3)6.