Cyclodextrin-based multifunctional supramolecular catalysts for aqueous CuAAC reaction

Abstract

As an excellent bioorthogonal reaction, CuAAC reaction has been widely used in biological research. In this work, three cyclodextrin derivatives β-CD-3, β-CD-4 and CD-P were synthesized in different ways. Among them, use of trace amounts of the β-CD-3 could efficiently promote the CuAAC reaction under mild conditions. Only using 20 ppm concentration of β-CD-3-Cu(I), the TON of the reaction was up to 45,000, and the catalyst still has high catalytic activity after repeated cycling, which may be attributed to its chelating structure formed by coordination with copper more stable than β-CD-4-Cu(I) and CD-P-Cu(I). In addition, we have also proved that the construction of supramolecular catalytic systems can effectively achieve extracellular click reactions at ultra-low concentrations, and therefore can be applied to the synthesis of various functional compounds such as catalysis, imaging, targeting and medicine.