Stereoselective Synthesis of Cyclic Guanidines by Directed Diamination of Unactivated Alkenes.

A method for a directed stereoselective guanidinylation of alkenes is described. The guanidine unit can be delivered as an intact fragment by a hydroxy or carboxy group, usually with a high level of stereocontrol. After the guanidine delivery, the directing group can be cleaved under exceptionally mild conditions, typically by alcoholysis in the presence of acetic acid. Broad functional group tolerance and mild reaction conditions for the cycloguanidilation suggest applications in medicinal chemistry and natural products synthesis.