NHCs , applications medicinal chemistry

This article presents the principles known so far for the synthesis of metal complexes containing stable carbenes, including the preparation of the relevant carbene precursors. The use of some of these compounds in transition-metal-catalyzed reactions is discussed mainly for ruthenium-catalyzed olefin metathesis and palladium-Znickel-catalyzed coupling reactions of aryl halides, but other reactions will be touched upon as well. Chapters about the properties of metal- carbene complexes, their applications in materials science and medicinal chemistry, and their role in bioinorganic chemistry round the survey off. The focus of this review is on ZV-heterocyclic carbenes, in the following abbreviated as NHC and NHCs, respectively. 

Promising applications for metal-NHC compounds in materials science and medicinal chemistry are based on the strong metal-carbon bond and the high donor capability of the NHC. The most extensive investigations have been carried out in the field of homogeneous catalysis. Here, NHCs have to be considered as typical directing or innocent spectator ligands, best comparable to trialkylphosphines. The recent successful applications of NHCs in ruthenium-catalyzed olefin metathesis... 

In 2013, the Hui group developed an efficient NHC-catalyzed stereoselective aza-Michael-Michael-lactonization cascade reaction of 2-amino phenyl-enones and 2-bromoenals. Functionalized tetrahydroquinolines with three consecutive stereogenic centers were obtained in high yields with excellent diastereo- and enantioselectivity. This approach is attractive due to the mild reaction conditions and the potential application of the products in medicinal chemistry. In addition, this strategy extends the scope of NHC catalysis and provides a simple protocol for the NHC-catalyzed cascade reaction (Scheme 7.100). 

Among the different fields of applications characterizing the extremely versatile chemistry of poly-NHC complexes, bio-organometaUic chemistry is one of the most recent and unexplored, and thereby it is a very appealing and fertile research topic. The first reports about the medicinal... 

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