Copper-catalyzed synthesis of monosubstituted carbodiimides from aromatic amines.

Carbodiimides, which contain the NCN group, are important intermediates in organic synthesis, especially for building nitrogen-containing heterocycles. Traditional methods often need harsh conditions, toxic cyanide sources, or costly catalysts, which limit their practicality. Here, we present a mild and efficient copper-catalyzed method for the direct synthesis of monosubstituted carbodiimides from aromatic amines, using malononitrile as a safe and accessible cyanide source. The reaction occurs under normal conditions, providing a cost-effective and environmentally friendly alternative to standard methods. This technique achieves high selectivity for monosubstituted carbodiimides across a wide range of substrates, representing sustainable and practical progress in carbodiimide production. This reaction represents a significant advancement in synthetic organic chemistry, as there have been no prior reports of the synthesis of monosubstituted carbodiimides in the literature.