Immobilization of N-Heterocyclic Carbene Compounds: A Synthetic Perspective.

Over the course of the past 15 years the success story of N-heterocyclic carbene (NHC) compounds in organic, inorganic, and organometallic chemistry has been extended to another dimension. The immobilization of NHC compounds, undergoing continuous diversification, broadens their range of applications and leads to new solutions for challenges in catalytic and synthetic chemistry. This review intends to present a synthetic toolkit for the immobilization of NHC compounds, giving the reader an overview on synthetic techniques and strategies available in the literature. By individually summarizing and assessing the synthetic steps of the immobilization process, a comprehensive picture of the strategies and methodologies for the immobilization of NHC compounds is presented. Furthermore, the characterization of supported NHC compounds is discussed in detail in order to set up necessary criteria for an in-depth analysis of the immobilized derivatives. Finally, the catalytic applications of immobilized NHC compounds are briefly reviewed to illustrate the practical use of this technique for a broad variety of reaction types.