Recent Advances in Functionalized Isocyanide Synthesis and Natural Products Containing the Isocyano Functional Group and Their Biological Properties

Highly functionalized isocyanides, particularly those with a stereogenic center, are more difficult to access compared to simple isocyanides, which are commercially available. Several research groups have reported the synthesis of novel isocyanides, which constitute necessary reagents for the synthesis of pharmacologically active drugs. Likewise, natural compounds with isocyano functionality are well-known in many kingdoms of living organisms. Of course, the origin of such a functional group, as well as the mechanisms that have evolved in biosynthetic pathways to allow isocyanide synthesis, are critical biochemical questions. Many natural isonitriles have been demonstrated to have significant antibacterial, fungicidal, or anticancer effects. Hence, synthetic techniques are of great interest. In this manuscript, we have reviewed the synthesis of both simple and functionalized isocyanides, with particular emphasis on naturally occurring isocyanides derived from terrestrial and marine sources, including isonitrile (R-N≡C-) natural products (NPs).