The invention relates to an innovative method for synthesis of cyclic amidines. The synthesis starts from a β-, γ- or δ-lactone which is twofold brominated. After esterification of the carboxyl function, the bromine atoms are nucleophilically substituted and the corresponding diamino compound is obtained. The ring closure to the cyclic amidine is accomplished subsequently by reaction with orthoester, imidate or thioimidate. Owing to interposing additional steps for recovery of the diamino compound in enantiomerically pure form, the enantiomers of the cyclic amidines can be stereoselectively synthesized.
