A direct isoxazole synthesis employing N-heterocyclic carbenes (NHCs) as single-carbon synthons is reported. Using imidazolium salts as carbon donors, nitroalkenes are transformed into 5-amino-substituted isoxazoles via a nucleophilic addition–cycloaddition–ring opening–hydrolysis cascade reaction. This mild process simultaneously constructs C–O and C–C bonds, accessing products that are difficult to obtain by classical methods. The proposed reaction mechanism is supported by both experimental and computational studies. Several derivatives exhibit broad-spectrum antifungal activity, highlighting their potential as fungicide leads.
Zheng et al. (Sat,) studied this question.