New methods for the preparation of aryl 2-iminoimidazolidines

A divergent strategy for the synthesis of 1-aryl- and 2-aryl-2-iminoimidazolidines is presented. Cyclization of N-Boc-N′-aryl-N′′-(2-hydroxyethyl)guanidines in the presence of methanesulfonyl chloride and triethylamine or sodium hydride at 0 °C affords the corresponding 2-iminoimidazolidines in good yields.