Françoise Rose-Munch

Highly regioselective aromatic substitution on a diaryloxidetricarbonylchromium complex

Abstract : Ortho-substituted diaryloxide tricarbonylchromium (O) complexes PhOAr-Cr (CO)3, treated with carbanions Nu−, give, after acid quenching, paradisubstituted complexes NuAr-Cr (CO)3 via a 1,3-hydride migration followed by elimination of phenol : the overall sequence of the reaction consists in a regioselective meta substitution of the phenoxy group by the nucleophile.

cine and tele Nucleophilic Substitutions in (η6-Arene)tricarbonylchromium and Tricarbonyl(η5-cyclohexadienyl)manganese Complexes

Addition of a nucleophile to an (η6-arene)tricarbonylchromium or a tricarbonyl(η5-cyclohexadienyl)manganese complex substituted with a leaving group X (X = F, Cl, OMe, OPh, NR2) affords (after treatment with acid) new complexes with the same η6 or η5 hapticity. The overall reaction involves addition of the nucleophile ortho, meta, or para with respect to the leaving group and HX elimination. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Structure radiocristallographique du veratrole-chrome-tricarbonyle; etudes RMN 1H d'arene-chrome-tricarbonyles ortho-disubstitues et regioselectivite de l'addition α-cyanocarbanion

Abstract The structure of veratroletricarbonylchromium in the solid state has been determined by X-ray study. The projection of the chromium atom on the arene plane is displaced by 0.06(1) A from the center of symmetry of the benzene ring toward the side opposite to the methoxy groups, and the conformation of the tripod is almost staggered with regard to the aromatic ring. Comparison between the 1 H NMR spectra of veratrole and veratroletricarbonylchromium shows that the protons ortho to the methoxy groups are less shielded during the complexation of veratrole with the Cr(CO) 3 entity and their chemical shift occurs at lower field. From these observations, it is deduced that there is a relationship between the chemical shifts of these protons and the regioselectivity of the addition to the aromatic ring of an α-cyanocarbanion. The same conclusion is extended to the case of other disubstituted arenetricarbonylchromium complexes.

Tricarbonyl(1-trimethylsilyl-2,3-dimethoxybenzene)chromium: A new conformation of the tricarbonylchromium entity with respect to a bulky substituent

Abstract Because of steric effects the Cr(CO) 3 group in tricarbonyl(1-trimethylsily]-2,3-dimethoxybenzene)chromium does not take up an anti-eclipsed conformation with respect to the trimethylsilyl group, but instead adopts the opposed conformation nearly eclipsing that group.

Substitution nucléophile aromatique cine en série arènetricarbonylchrome

Abstract 2-Lithio-2-phenyl-1,3-dithiane reacts with p -chlorotoluenetricarbonylchromium to give, after treatment with CF 3 CO 2 H, the sole cyclohexadiene isomer 1-methyl-4-chloro-5(2′-phenyl-1′,3′- dithiane)-1,3-cyclohexadiene, which was characterized by X-ray crystallography.

Heteronuclear (WFe) and homonuclear (FeFE) μ-alkylidene complexes of transition metals from mononuclear terminal carbene complexes. crystal structures of {WFe[μ-η1, η3-C(OCH2CH3)(CHCHCH3](CO)8} and [fe2{μ-η2,η3-C[OCH2CH3[CHC(OCH2CH3)(CH3]}(CO)6

Abstract The reactions of mononuclear carbene complexes of W and Fe of the type CO) m MC(OR)(CH 2 n CHCR′″ (M  = FE, W; m = 4 and 5; n = 0, 2, 3; R′, R″ = C, CH 3 , OEt) with Fe(CO) 5 have been studied. In all cases the reaction leads to new hetero (WFe) or homo (FeFe) μ-alkylidene complexes, the position of the double bond depending strongly on n .

An enantiomerically pure tricyclic isoindoline system by cyclisation of tricarbonyl[η6-(R)-N-cyanomethyl-4-phenyloxazolidine]chromium

Abstract The isolation of isoindoline 4 by oxidative trapping indicates that a tricyclic η5 complex is a contributing form of the anion derived from the title compound 3.

Bimetallic π-conjugated complexes modulated by a carbonyl spacer: synthesis of arenetricarbonylchromium–ferrocene derivatives

Abstract Heterobimetallic complexes modulated by a carbonyl spacer have been prepared in the case of arenetricarbonylchromium and ferrocene derivatives via Claisen–Schmidt condensations.

Tricarbonyl-η6-[(2-thiophenyl)arene]- and -η6-[(2-thiophenyl)carbonylarene]- chromium Complexes: Preparation and Conformational Study

The cross coupling reaction of (p-chloroanisole)tricarbonylchromium complex (1) with thiophene derivatives under palladium-catalyzed conditions leads to the selective formation of tricarbonyl-η6-[(2-thiophenyl)arene]- or -η6-[(2-thiophenyl)carbonylarene]chromium complexes (2 or 3) depending on reaction conditions. The conformation of complexes 2 and 3 in the solid state as well as in solution are reported.

Etude conformationnelle du dimethyl-2,3- triisopropylsilyloxybenzenetricarbonylchrome et regioselectivite de sa lithiation

Abstract In the solid state, 2,3-dimethyltriisopropylsiloxybenzenetricarbonylchromium adopts an almost eclipsed conformation with respect to the siloxy group, and in solution the major conformer has the same conformation. Lithiation of this complex occurs regioselectively at the meta position towards the siloxy group.