Ag(I)-catalyzed rapid access to 2-amino-4-methylenethiazolines with potential application in bioconjugation chemistry

An Ag(I)-catalyzed tandem addition-cyclization of isothiocyanate and propargylamine was successfully applied to the synthesis of 2-amino-4-methylenethiazolines. This route features unprecedented fast reaction rate with full conversion reached within 10 min at room temperature for aromatic isothiocyanates, as well as excellent chemoselectivity for exocyclic products. The application of this strategy is further highlighted by the accelerated bioconjugation of propargylamine with fluorescein isothiocyanate (FITC) under Ag(I)-catalysis.