Nature Communications, Published online: 18 June 2026; doi:10.1038/s41467-026-74600-0 Authors present an ErCl₃-catalyzed cyanation of both aliphatic and aryl ketone hydrazones for the facile access of C(alpha)-tetrasubstituted alpha-hydrazino nitriles in up to 96% ee, by using a sterically confined pyridinebisoxazoline (PYBOX) ligand featuring a sulfonyl group at the pyridine C4 position.