N-Heterocyclic carbene-catalyzed 1,3-dipolar cycloaddition reactions: A facile synthesis of 3,5-di- and 3,4,5-trisubstituted isoxazoles
A first example of organo-N-heterocyclic carbene (NHC) catalyzed click-type fast 1,3-dipolar cycloaddition of nitrile oxides with alkynes was developed for the regioselective synthesis of 3,5-di- and 3,4,5-trisubstituted isoxazoles. Triethylamine (Et