Six-membered ring oxygen and nitrogen heterocycles are formed stereoselectively by C–H insertion of donor/donor carbenes.

A copper-mediated multi-component reaction was developed through isocyanide insertion into N-H bonds of less active secondary arylamines. This approach leads to an efficient synthesis of unsymmetrical tetrasubstituted ureas in one pot.

An efficient method for the regioselective synthesis of pharmacologically relevant polysubstituted Δ(2)-isoxazolines is based on the copper-mediated direct transformation of simple terminal alkynes and alkenes. The overall process involves the formation of four chemical bonds with inexpensive and readily available copper nitrate trihydrate as a novel precursor of nitrile oxides. The reaction can be easily handled and proceeds under mild conditions.