Chapter 9, Problem 9.81P

Aziridines are heterocycles that contain an N atom in a three-membered ring. Like epoxides, aziridines are strained and reactive because the $60°$ bond angles of the three-membered ring deviate greatly from the theoretical tetrahedral bond angle. One step in the synthesis of the drug oseltamivir (trade name Tamiflu, Section 3.2) involves the conversion of amine X to diamine Y, a reaction that occurs by way of an intermediate aziridine. Draw a stepwise mechanism f or the conversion of X to Y. Indicate the structure of the aziridine intermediate, and explain the trans stereochemistry of the two

amines in Y.