Using 2-stanna-1,3-dioxepane (DSDOP) as cyclic initiator either neat epsilon-caprolactone (epsilon-CL) or mixtures of epsilon-CL and L-lactide were polymerized in bulk. The resulting tin-containing macrocyclic polylactones were reacted with an excess of N-protected amino acid or dipeptide 4-chlorothiophenyl esters. It was shown that the coupling of amino acid thioaryl esters and tin-containing macrocycles does not involve any racemization. The cleavage of Boc groups with trifluoroacetic acid proved to be feasible but not the hydrogenolytic cleavage of the Z-group.