Bioorthogonal chemistry can be used for the selective modification of biomolecules without interfering with any other functionality that might be present. Recent developments in the field include... Show moreBioorthogonal chemistry can be used for the selective modification of biomolecules without interfering with any other functionality that might be present. Recent developments in the field include orthogonal bioorthogonal reactions to modify multiple biomolecules simultaneously. During our research, we observed that the reaction rates for the bioorthogonal inverse‐electron‐demand Diels–Alder (iEDDA) reactions between nonstrained vinylboronic acids (VBAs) and dipyridyl‐s‐tetrazines were exceptionally higher than those between VBAs and tetrazines bearing a methyl or phenyl substituent. As VBAs are mild Lewis acids, we hypothesised that coordination of the pyridyl nitrogen atom to the boronic acid promoted tetrazine ligation. Herein, we explore the molecular basis and scope of VBA–tetrazine ligation in more detail and benefit from its unique reactivity in the simultaneous orthogonal tetrazine labelling of two proteins modified with VBA and norbornene, a widely used strained alkene. We further show that the two orthogonal iEDDA reactions can be performed in living cells by labelling the proteasome by using a nonselective probe equipped with a VBA and a subunit‐selective VBA bearing a norbornene moiety. Show less
This thesis describes the synthesis of oligonucleotide conjugates by means of the strain induced [2+3] dipolar cycloaddition is described. To this end, dibenzocyclooctyne containing phosphoramidite... Show moreThis thesis describes the synthesis of oligonucleotide conjugates by means of the strain induced [2+3] dipolar cycloaddition is described. To this end, dibenzocyclooctyne containing phosphoramidite building blocks were synthesized. These building blocks were subsequently used in the solid phase synthesis of RNA and DNA oligonucleotides yielding dibenzocyclooctyne containing oligonucleotides. These oligonucleotides were used in strain induced cycloadditions with a variety of azides e.g. fluorescent labels, oligosaccharides, oligopeptides and bovine serum albumin yielding the corresponding conjugates. Additionally, the synthesis of D-arabinose and D-ribose derived C-glycosides is described. These nucleoside derivatives were obtained from D-ribose and D-arabinose C-1 substituted hemi-ketals in BF3OEt2-triethyl silane mediated reductions. The results and mechanism regarding the stereoselectivity in these reductions are discussed. Show less
