Kinetics of Strain-Promoted Alkyne-Nitrone Cycloadditions (SPANC) with Unprotected Carbohydrate Scaffolded Nitrones.

The use of unprotected carbohydrate-derived nitrones as partners in strain-promoted alkyne-nitrone cycloadditions was investigated as a new tool for bioconjugation. The observed second-order reactions displayed rate constants of 3.4 × 10-5.8 × 10 M s, which is the common order of magnitude of reaction kinetics with other simple aliphatic or aromatic nitrones. Applicability of this method to aqueous media was demonstrated by performing a one-pot protocol, which combines sequential formation of the nitrone and cycloaddition with cyclooctyne in water.