“…These strategies are based on different starting materials or novel reagent systems. Examples include the generation of isocyanates from amines using CO 2 , or methanol, azides using CO, carbamates by degradation, amides by the Curtius reaction, hydroxamic acids by the Lossen reaction, isonitriles by oxidation, formamides by N–H activation, o -methyl-N-nitroisourea by Krapcho-type dealkylation, and aryl chloride and sodium cyanates by Pd-catalyzed cross-coupling . Nevertheless, the development of a dependable synthesis under mild conditions for isocyanates, along with their use in the preparation of N -containing unsymmetrical carbonyl compounds, remains a significant subject …”