Organozinc reagents transition-metal-catalyzed cross-coupling

Transition-Metal-Catalyzed Cross-Coupling Reactions of Organozinc Reagents... 

The introduction of a polyfluorinated chain is not so easy as that of an alkyl chain. Transition metal catalyzed cross-coupling of Grignard reagents and organozinc compounds are inefficient in the synthesis of polyfluorinated 3-alkylthiophene. The copper-catalyzed perfluoroalkylation results in the formation of 2-and 3-substituted thiophenes, which are difficult to separate from each other. The reaction of fluorinated alkylmagnesium iodide with 3-formylthiophene, follwed by reduction with lithium aluminum hydride, gave (22) in an overall yield of 40% [27]. 

Organozinc compounds tolerate a broad range of functional groups. Cross-coupling reactions between organozinc reagents and electrophiles such as orgauic hahdes are catalyzed by transition metal complexes. However, examples for the selective... 

---