Transition-Metal-Catalyzed Cross-Coupling Reactions of Organomagnesium Reagents

Transition-Metal-Catalyzed Cross-Coupling Reactions of Organomagnesium Reagents 

Another important feature of the Grignard reagents is the Lewis acidity of magnesium salts thaL in many cases, can help activate the electrophilic partner, thereby often enhancing the variety of electrophiles suitable for coupling. This enhanced reactivity is, however, responsible for the major drawback associated with the use of organomagnesiums, namely, the reduced functional group tolerance. 

The metal-catalyzed cross-coupling of aryl-, heteroaryl-, and alkenyhnagnesium derivatives is a broad-scope transformation that has found many synthetic applications C(sp )-C(sp ) couplings are by far the most common. Catalysts by nickel, palladium, and iron complexes is most widespread, but the emerging fields of cobalt and manganese catalysis can also provide useful alternatives. 

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Transition-Metal-Catalyzed Cross-Coupling Reactions of Organomagnesium Reagents 385 5.3.2.1 Palladium-Catalyzed Cross-Coupling Reactions... 

The transition metal catalyzed carbon-carbon bond formation between organomagnesium reagents and aryl (vinyl) halides has been one of the pioneering entries into cross-coupling chemistry. The reaction has been widely utilized since than in azine chemistry,22 with the limitation that the functional group tolerance of Grignard reagents is only moderate. Here only some of the more recent developments will be mentioned. 

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