Direct conversion of epoxides to aziridines was achieved with guanidines as a nitrogen source. Stereochemical inversion at the chiral centers of epoxides was observed without loss of optical purity.
aziridinomitosene skeleton, a basic core of mitomycin antibiotics, was straightforwardly prepared from N‐(p‐toluenesulfonyl)indole‐2‐carboxaldehyde in 16% overall yield by successive reactions of guanidiniumylide‐mediated aziridination, InCl3‐catalyzed epimerization of trans‐3‐(indol‐2‐yl)aziridine‐2‐carboxylate, leading to the cis‐derivative, and dehydrative cyclization.