Eric Rose

Chimie organometallique ☆: XXII. Synthese d'arenes substitues par addition d'un nucleophile a un arene chrome tricarbonyle puis par decomplexation oxydante du metal

Abstract The product distribution obtained in addition reactions of −CH(CH3)CN to an arenechromium tricarbonyl is studied. The major product obtained after oxidative removal of the metal corresponds to nucleophilic addition on an arene carbon atom which is in an eclipsed position with respect to the carbonyl group of the Cr(CO)3 unit of the most stable conformer. The synthesis of the corresponding acid represents an example of arenechromium tricarbonyl chemistry applied to synthesis of an organic compound having pharmaceutical properties and which by classical methods could only be synthesized via a multi step process.

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.

Chimie organometallique: XXX. Etude par resonance magnetique nucleaire du proton et par radiocristallographie du N-methylindolechrome-tricarbonyle

Abstract The structure of N -methylindolechromium tricarbonyl ( 4 ) in the solid state has been determined by X-ray crystallography. The projection of the chromium atom on the N -methylindole plane does not coincide with the center of symmetry of the benzene ring; the tripod is distorted and the overall conformation of the complex is gauche rather than eclipsed. Study of the 1 H NMR spectrum of complex 4 in solution at +20°C and −38°C leads to similar conclusions. The results explain the nucleophilic attack at carbon atoms 4 and 7 of complex 4 .

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.

Chimie organometallique : XXIII Synthese d'arenes substitues par addition d'un nucleophile a un cation d′η6-arene η5-cyclopentadienyl-fer puis par decomplexation du metal

Abstract The product distribution obtained by the addition of −CH(CH 3 )CN to an η 6 -arene-η 5 -cyclopentadienyliron cation is studied. The formation of the substituted arene from η 5 -cyclohexadienyl-η 5 -cyclopentadienyliron is described.

Synthese de la meso-α,β bis(diamino-2,6 phenyl) octamethyl porphyrine

Abstract α,γ-Meso bis-(2,6-diaminophenyl) octamethyl porphyrin and derivatives have been prepared by an easy synthesis avoiding the separation of stereoisomers and represent a new kind of tetrafunctionalised porphyrin.

Highly diastereoselective cyclopropanation of α-methylstyrene catalysed by a C2-symmetrical chiral iron porphyrin complex.

A new chiral iron porphyrin-based catalyst performed α-methylstyrene stereoselective cyclopropanation with excellent yields (up to 99%), enantio- and diastereoselectivities (ee(trans) up to 87%, trans/cis ratios up to 99 : 1) and outstanding TON and TOF values (up to 20,000 and 120,000 h(-1) respectively).