Synthetic Strategies for Free & Stable N-Heterocyclic Carbenes and Their Precursors

Recently, chemical cross coupling reactions have emerged as a powerful tool in the hands of synthetic organic chemist to synthesize complicated organic scaffolds like drugs, natural products, optical devices and industrially important materials. Stable N-Heterocyclic Carbene (NHC) acts as an important catalyst system in various cross coupling reactions. This review describes various strategies used for the synthesis of free and stable NHCs. Historical developments made in the propagation of the idea of free and stable carbene have also keenly been illustrated in the introduction of this review.