Synfacts 2009(1): 0077-0077  
DOI: 10.1055/s-0028-1087445
Metal-Mediated Synthesis
© Georg Thieme Verlag Stuttgart ˙ New York

Microwave-Enhanced Zincation of Arenes and Heteroarenes

Contributor(s):Paul Knochel, Andrei Gavryushin
S. Wunderlich, P. Knochel*
Ludwig-Maximilians-Universität, München, Germany
High Temperature Metalation of Functionalized Aromatics and Heteroaromatics using (tmp)2Zn×2MgCl2 ×2LiCl and Microwave Irradiation
Org. Lett.  2008,  10:  4705-4707  
Further Information

Publication History

Publication Date:
18 December 2008 (online)


Significance

Direct metalation of polysubstituted arenes is a highly attractive method of their further functionalization, allowing straightforward routes toward complex industrially important molecules. The compatibility with functional groups makes the use of zincation preferable over the conventional lithiation or magnesiation reactions, offering an outstanding range of functional group compatibility. This method allows simple functionalization of relatively inactive substrates, which were formerly problematic for direct metalation.

Comment

The use of this reagent for the zincation of electron-poor heterocycles has been ­reported earlier (S. H. Wunderlich, P. Knochel ­Angew. Chem. Int. Ed. 2007, 46, 7685). At room temperature, the metalation of simple benzoate esters is too slow (>100 h for completion), but the use of microwave irradiation enhances the reaction to a practical rate.

Review: For a review on microwave-assisted synthesis, see: C. O. Kappe Angew. Chem. Int. Ed. 2004, 43, 6250-6284.