Straightforward stereoselective access to cyclic peptidomimetics.

The preparation of cyclic dipeptide mimetics from chiral imino lactones derived from (R)-phenylglycinol is described. Key steps of the synthetic route included the fully stereoselective construction of a quaternary center, the formation of six-, seven-, or eight-membered lactams by means of an RCM cyclization, and the introduction of a new amino group within the lactam ring. The synthesis of a tripeptide mimetic is also reported.