Ru(II)-Salen-Catalyzed Asymmetric Aziridination

Significance

Using a rationally designed Ru(II)-salen catalyst, several N-sulfonyl azides, in the presence of terminal alkenes, were converted into the corresponding aziridine in good to excellent yield and enantioselectivity. Styrenes and 1,3-enynes were well tolerated, with reduced yields and selectivities with aliphatic terminal alkenes. Unlike other methods that employ N-sulfonyl azides as nitrene precursors, this method does not require photochemical activation and proceeds with mild thermal activation. In addition, the nitrogen protecting groups are easily cleaved allowing access to N-H aziridines under mild conditions.