Tetrazine- and trans -cyclooctene-functionalised polypept(o)ides for fast bioorthogonal tetrazine ligation

The inverse electron demand Diets-Alder (IEDDA) reaction-initiated ligation between 1,2,4,5-tetra-zines (Tz) and trans-cyclooctenes (TCO) is one of the fastest bioorthogonal reactions known today and is therefore increasingly used for in vivo click chemistry. Described herein is the synthesis of Tz- and TCO-functionalised polypeptides, polypeptoids and polypeptide-block-polypeptoids (polypept(o) ides) by ring-opening polymerisation of the corresponding N-carboxyanhydrides using Tz- or TCO-functional amine initiators. Despite the reactivity of tetrazines, polymers with low dispersity and high end group integrity can be obtained as observed by gel permeation chromatography (GPC), nuclear magn…