Studies on some selective and competitive substitution reactions of cyclopentadienyliron complexed chloronitrobenzenes with amines as nucleophiles

Abstract

Can. J. Chem. 67, 1618(1989. Nucleophilic substitution reactions of the (q6-0-, -m-, or -p-chloronitrobenzene)(q5-cyclopentadienyl)iron cation (2a, 2b, or 2c, respectively) with aniline, n-butylarnine, or pyrrolidine as nucleophile were investigated. It was found that only selective displacement of the nitro group occurred for reactions with aniline. For reaction with n-butylamine or pyrrolidine, o-isomer 2a resulted in the selective displacement of only the chloro group, giving rise to the (q6-o-n-butylaminonitrobenzene)(q5-cyclopentadieny1)iron cation (5a) or the (q6-o-nitro-~-pyrrolidinylbenzene)(q5-cyclopentadieny1)iron cation (7a), respectively. With the m-or p-isomer 2b or 2c, reaction with n-butylamine or pyrrolidine gave a mixture of substitution products from competitive displacements of both chloro and nitro groups, the major product from the m-isomer being derived from displacement of the chloro group while the major product from the p-isomer resulted from displacement of the nitro group. Possible interpretations of these results on the basis that the basicity of the nucleophile and the combined inductive effects of the nitro and chloro substituents would play important roles are presented.Key words: (q6-o-, -m-, and -p-chloronitrobenzene)(q5-cyclopentadienyl)iron cations, nucleophilic substitution reactions, aniline, n-butylamine, pyrrolidine.ALAA S. ABD-EL-AZIZ, ADAM P I~R K O , CHOI CHUCK LEE et RONALD G. SUTHERI-AND. Can. J. Chem. 67, 1618(1989. On a ktudik les reactions de substitutions nuclkophiles des cations (q6-0-, -m-ou -p-chloronitrobenzbne)(q5-cyclopentadikny1)fer (respectivement 2a, 2b ou 2c) avec l'aniline, la n-butylamine ou la pyrrolidine. On a trouvi que, avec l'aniline, il ne se produit qu'un dkplacement sklectif du groupement nitro. Pour les reactions de la n-butylamine ou de la pyrrolidine avec l'isombre ortho, 2a, on n'observe que le dkplacement sklectif du groupement chloro conduisant respectivement aux cations (q6-o-n-butylaminonitrobenzbne)(q5-cyclopentadiknyl)fer (5a) ou (q6-o-n-nitro-~-pyrrolidinylbenzbne)(q5-cyclopentadiCny1)fer (7a). Avec les isombres mita ou para (2b ou 2c), les rkactions avec la n-butylamine ou la pyrrolidine conduisent 9 des mClanges de produits de substitution provenant des rkactions de substitutions compktitives des groupements chloro et nitro; le produit majeur obtenu 9 partir de l'isombre rne'ta provient de la substitution du groupement chloro alors que le produit majeur obtenu 9 partir de l'isombre para provient de la substitution du groupement nitro. On prksente des interprktations possibles de ces rtsultats qui sont baskes sur les basicitts relatives des nuclkophiles et sur l'hypothbse que les effets inductifs combinks des substituants nitro et chloro joueraient un rBle important.Mots clis : cations (q6-o-, -m-ou -p-chlor~nitr~ben~~ne)(q5-cyclopentadiknyl)fer, rkactions de substitutions nucleophiles, aniline, n-butylarnine, pyrrolidine.[Traduit par la revue]The displacement of the chloro group in the (q6-chlorobenzene) ( q 5-cyclopentadienyl) iro...

Iron-Assisted Nucleophilic Aromatic Substitution on Solid Phase

“…All attempts to perform an S N Ar reaction with the very weak nucleophile aniline failed. This is in accordance with investigations of Abd-el-Aziz et al in which aniline replaces only electron-withdrawing leaving groups such as a nitro group, but not a chlorine atom in η 6 -aryl-η 5 -cyclopentadienyliron(II) complexes …”

(Arene)Cr(CO)3 Complexes: Aromatic Nucleophilic Substitution

“…The (1,2-difluorobenzene)FeCp + complex underwent smooth double substitution with phenethyl amine, whereas a dichloro complex led to monosubstitution. Replacement of a nitro group in h 6 -nitrobenzeneFeCp + is possible with O, S, and N-nucleophiles [70,80,81]. The nitroarene complexes, which are not known in the Cr(CO) 3 series, are prepared by oxidation of the corresponding aniline complexes.…”

Efficient Synthesis of Arylated Carbazole from Cyclopentadienyliron Complexes

“…Nucleophilic substitution of arene complexes to a metal moiety with a variety of different nucleophiles have been reported by Abd-El-Aziz and other researchers. − These metal moieties include tricarbonylchromium, tricarbonylmanganese, and cyclopentadienyliron. Due to the reactivity and relatively simple synthetic methods associated with the cationic cyclopentadienyliron complexes of arene, a large number of functionalized aromatic and biologically active compounds have been prepared using this methodology. − Many aryl-substituted compounds have been synthesized by the nucleophilic substitution of organo-iron complexes followed by photochemical liberation of free arenes. − …”