Metal-free synthesis of triarylated (Z)-nitrones via H₂O-mediated 1,3-dipolar transfer under aerobic conditions

Ke Chen, Wen-Juan Hao, Shu-Jiang Tu,* Bo Jiang*

A new and environmentally benign protocol aimed at the generation of triarylated (Z)-nitrones in generally good yields has been developed via metal- and catalyst-free H₂O-mediated 1,3-dipolar transfer reaction of para-quinone methides (p-QMs) with diarylated nitrones under aerobic conditions. The purification of these products only needs to be recrystallized by the mixed solvent of small amount of petroleum ether and ethyl acetate, thereby avoiding traditional chromatography. The current new 1,3-dipolar strategy features broader substrate scope, green process and mild conditions.

Green Chem. 2019, 21, 675-683