Subscribe to RSS
DOI: 10.1055/s-0028-1087445
Microwave-Enhanced Zincation of Arenes and Heteroarenes
Contributor(s):Paul Knochel, Andrei GavryushinLudwig-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
Publication History
Publication Date:
18 December 2008 (online)
Key words
arene metalation - microwave - arylzinc compounds
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.