Preparation of Optically Active Piperazines from Ethyl (S)-2-(2-Alkyl-1-aziridinyl)acetates

Reaction of ethyl (S)-2-(2-alkyl-1-aziridinyl) acetates with boron trifluoride etherate in a large excess of ethylamine or ammonia gives the corresponding optically active piperazines in good yields. These piperazines retain the configuration of the starting aziridines.