Polysubstituted guanidine functionality occurs as the key component for the expression of the biological activity in numerous natural compounds. The wide range of biological activities found for guanidines has motivated the development of many reagents for their preparation. One class of reagents achieves guanylation by the addition of a nucleophilic amine onto a cyanamide, 1 or a carbodiimide. 2-6a The carbodiimide is often prepared in ...