Azide alkyne Huisgen cycloaddition

The Azide alkyne Huisgen cycloaddition is a Huisgen cycloaddition or 1,3-dipolar cycloaddition between an azide and a terminal alkyne to a triazole. This cycloaddition is considered the cream of the crop of click chemistry. Huisgen {{Ref|1}} was the first to understand the scope of this organic reaction.

Related Topics:
Huisgen cycloaddition - 1,3-dipolar cycloaddition - Azide - Alkyne - Triazole - Click chemistry - Organic reaction

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In the reaction above {{Ref|2}} azide 1 reacts neatly with alkyne 2 to the triazole 3 as a mixture of 1,4 adduct and 1,5 adduct at 98 °C in 18 hours. Regioselectivity can be improved in a copper catalysed reaction, especially if Tim's Ligand is used. NH-1,2,3-triazoles are also prepared from alkynes in a sequence called the Banert cascade.

Related Topics:
°C - Regioselectivity - Copper - Catalysed - Tim's Ligand - Banert cascade

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The utility of this click reaction has also been demonstrated in the polymerization reaction of a bis-azide and a bis-alkyne with copper(I) and Tim's Ligand to a conjugated fluorene based polymer {{Ref|3}}. The degree of polymerization easily exceeds 50 and with a stopper molecule such as phenyl azide well defined phenyl end-groups are obtained.

Related Topics:
Polymerization - Tim's Ligand - Conjugated - Fluorene - Polymer - Degree of polymerization - Phenyl azide - Phenyl - End-group

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Click chemistry also effectively couples polystyrene and bovine serum Albumin (BSA) {{Ref|4}}. The result is an amphiphilic biohybrid. BSA contains a thiol group at Cys-34 which is functionalized with an alkyne group. Polystyrene has an azido end-group and the coupling takes place in a THF / phosphate buffer solution with Copper(II) sulfate and ascorbic acid. In water the biohybrid micelles with a diameter of 30 to 70 nanometer form aggregates.

Related Topics:
Polystyrene - Bovine - Serum - Albumin - Amphiphilic - Thiol - Cys - Alkyne - Azido - End-group - THF - Phosphate - Buffer solution - Copper(II) sulfate - Ascorbic acid - Micelle - Diameter - Nanometer

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