Hydroxyaminolactams have been used as constrained surrogates of the Ser-Leu dipeptide in the synthesis of analogues of the cycloheptapeptide stylostatin 1 (2). The rate of cyclization through formation of the Ile-Pro amidebond allowed us to prove that the valerolactams used induced a turn in the linear precursor. Ring closure at the Pro-Phe amidebond was much quicker and provided access to larger amounts