Modified Guanidines as Potential Chiral Superbases. 1. Preparation of 1,3-Disubstituted 2-Iminoimidazolidines and the Related Guanidines through Chloroamidine Derivatives

Modified guanidines were explored as potential chiral superbases. Thus, chiral 1,3-dimethyl-2-iminoimidazolidines with or without 4, 5-diphenyl groups, their guanidinium salts, and the 2-iminoimidazolidines with (S)-1-phenylethyl groups on the ring nitrogens were prepared by treatment of 2-chloroimidazolinium chlorides with appropriate amines. Bicyclic guanidines were also prepared from a prolinamide using a similar procedure.