Organomagnesium reagents occupy a central position in synthetic organic and organometallic chemistry. Recently, the halogen-magnesium exchange has considerably extended the range of functionalized Grignard reagents available for synthetic purposes. Functional groups such as esters, nitriles, iodides, imines, or even nitro groups can be present in a wide range of aromatic and heterocyclic organomagnesium reagents. Also various highly functionalized alkenyl magnesium species can be prepared. These recent developments as well as new applications of organomagnesium reagents in cross-coupling reactions and amination reactions will be covered in this Review.

The addition of functionalized arylmagnesium halides to nitroarenes in THF (-20 degrees C, 2 h) provides, after reductive workup (FeCl(2), NaBH(4)), various polyfunctional diarylamines in 63-86% yield. Heterocyclic arylated amines can be prepared by this one-pot procedure. A mechanistic rationale of this reaction is given.

Magnesiumverbindungen spielen eine zentrale Rolle in der präparativen organischen und metallorganischen Chemie. Seit kurzem ermöglicht der Halogen‐Magnesium‐Austausch den Zugang zu einer Reihe funktionalisierter Grignard‐Reagentien. Ester‐, Nitril‐, Iod‐ und Iminfunktionen und sogar Nitrogruppen können in einer breiten Reihe aromatischer und heterocyclischer Organomagnesiumverbindungen vorhanden sein. Auch hoch funktionalisierte Alkenylmagnesiumspezies können auf diese Weise generiert werden. Diese neuen Entwicklungen sowie die Anwendung von Organomagnesiumreagentien in Kreuzkupplungen und Aminierungsreaktionen werden in diesem Aufsatz eingehend beschrieben.

P r e p a r a t i o n o f F u n c t i o n a l i z e d A r y l m a g n e s i u m R e a g e n t s Abstract: Functionalized magnesium reagents have been prepared via an iodine-magnesium exchange. These reagents can be either trapped directly with aldehydes or transmetallated to copper or zinc to participate in cross-coupling reactions. The iodine-magnesium exchange, represent a unique method for the preparation of aryl and heteroaryl magnesium reagents.

A one‐pot reaction sequence consisting of a Grignard reaction, allylation, and reduction provides new functionalized diarylamines in good yields (see scheme, Ts=toluene‐4‐sulfonyl, NMP=N‐methylpyrrolidine, TFA=trifluoroacetic acid). In the first step azoaryl tosylates, which are readily obtained from aromatic amines, are treated with a myriad of functionalized organomagnesium compounds.