Florence Mongin

Pyridine elaboration through organometallic intermediates: regiochemical control and completeness

Pyridines carrying heterosubstituents (such as carboxy, amido, amino, alkoxy or trifluoromethyl groups or solely individual halogen atoms) can be readily and site selectively metalated. Subsequent reaction with a suitable electrophile opens rational access to a wealth of new building blocks for the synthesis of biologically active compounds. This approach relies on organometallic methods, which are both efficacious and extremely flexible as far as the substitution site and the product structure are concerned (86 references).

Mixed AggregAte (MAA): A Single Concept for All Dipolar Organometallic Aggregates. 2. Syntheses and Reactivities of Homo/HeteroMAAs

Aggregates. 2. Syntheses and Reactivities of Homo/HeteroMAAs Florence Mongin* and Anne Harrison-Marchand* Equipe Chimie et Photonique Mol eculaires, Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS-Universit e de Rennes 1, Bât. 10A, Case 1003, Campus de Beaulieu, Avenue du G en eral Leclerc, 35042 Rennes C edex, France Laboratoire COBRA de l0Universit e de Rouen, INSA de Rouen, CNRS, UMR 6014 & FR 3038, IRCOF, Rue Tesni ere, 76821 Mont St Aignan C edex, France

New Syntheses of Substituted Pyridines via Bromine–Magnesium Exchange

Abstract Bromine–magnesium exchange using i PrMgCl in THF at room temperature on 2-, 3- and 4-bromopyridines allowed the synthesis of various functionalized pyridines. The methodology was successfully used for the synthesis of 4-azaxanthone. Moreover, single exchange reactions observed on 2,6-, 3,5-, 2,3- and 2,5-dibromopyridines, with complete regioselectivity in the case of 2,3- and 2,5-dibromopyridines, afforded substituted bromopyridines, which were then involved in a second exchange step to provide difunctionalized pyridines.

Syntheses of substituted pyridines, quinolines and diazines via palladium-catalyzed cross-coupling of aryl Grignard reagents

Abstract The palladium-catalyzed cross-coupling reactions between arylmagnesium halides (phenylmagnesium chloride, mesitylmagnesium bromide, 4-(methoxycarbonyl)phenylmagnesium chloride and 4-cyanophenylmagnesium chloride) and halopyridines allowed the synthesis of substituted pyridines. Owing to the remarkably mild conditions used (often below 0°C), the reaction could be extended to the use of functionalized halopyridines, haloquinolines and halodiazines.

Pyridylmagnesium chlorides from bromo and dibromopyridines by brominemagnesium exchange: A convenient access to functionalized pyridines

Various bromopyridines were converted to the corresponding pyridylmagnesium chlorides at room temperature by treatment with iPrMgCl. The resulting Grignard reagents were quenched by various electrophiles to afford functionalized pyridines. The brominemagnesium exchange of some dibromopyridines was also studied.

Bimetallic combinations for dehalogenative metalation involving organic compounds.

Organic Compounds David Tilly,† Floris Chevallier,† Florence Mongin,*,† and Philippe C. Gros*,‡,§ †Equipe Chimie et Photonique Molećulaires, Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS-Universite ́ de Rennes 1, Bat̂iment 10A, Case 1003, Campus de Beaulieu, Avenue du Geńeŕal Leclerc, 35042 Rennes Ced́ex, France ‡HECRIN, Universite ́ de Lorraine, SRSMC UMR 7565, Boulevard des Aiguillettes, 54506 Vandoeuvre-les̀-Nancy, France HECRIN, CNRS, SRSMC UMR 7565, Boulevard des Aiguillettes, 54506 Vandoeuvre-les̀-Nancy, France

Deprotonative cadmation of functionalized aromatics

This communication describes the deproto-metalation of a large range of aromatics including heterocycles using a newly developed lithium-cadmium base; the reaction proceeds at room temperature with an excellent chemoselectivity and efficiency, and proved to be regioselective in most cases.

Deprotonative metallation of ferrocenes using mixed lithium–zinc and lithium–cadmium combinations

A mixed lithium-cadmium amide and a combination of lithium and zinc amides were reacted with a range of ferrocenes; deprotonative mono- or dimetallation in general occurred chemoselectively at room temperature, as evidenced by subsequent quenching with iodine.

Tributylmagnesium ate complex-mediated bromine–magnesium exchange of bromoquinolines: a convenient access to functionalized quinolines

2-, 3- and 4-bromoquinolines were converted to the corresponding lithium tri(quinolyl)magnesates at −10°C by treatment with Bu3MgLi in THF or toluene. The resulting organomagnesium derivatives were quenched by various electrophiles to afford functionalized quinolines.

Regioselective ortho-lithiation of chloro- and bromo-substituted fluoroarenes

Deprotonation of fluoroarenes carrying chlorine or bromine as addnl. substituents occurred always at a position adjacent to a fluorine if accomplished with potassium tert-butoxide activated butyllithium or lithium 2,2,6,6-tetramethylpiperidide. For example, treatment of 1-chloro-4-fluorobenzene with potassium tert-butoxide/butyllithium (superbase reagent) gave 5-chloro-2-fluorobenzoic acid (86% yield) as the major product and a small amt. of 2-chloro-5-fluorobenzoic acid. [on SciFinder (R)]