Gold-catalyzed direct alkynylation of tryptophan in peptides using TIPS-EBX

• Main Authors: Gergely L. Tolnai, Jonathan P. Brand, Jerome Waser
• Format: Article
• Language: English
• Published: Beilstein-Institut 2016-04-01
• Series: Beilstein Journal of Organic Chemistry
• Subjects: alkynes; C–H functionalization; gold catalysis; hypervalent iodine; peptides
• Online Access: https://doi.org/10.3762/bjoc.12.74

The selective functionalization of peptides containing only natural amino acids is important for the modification of biomolecules. In particular, the installation of an alkyne as a useful handle for bioconjugation is highly attractive, but the use of a carbon linker is usually required. Herein, we report the gold-catalyzed direct alkynylation of tryptophan in peptides using the hypervalent iodine reagent TIPS-EBX (1-[(triisopropylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one). The reaction proceeded in 50–78% yield under mild conditions and could be applied to peptides containing other nucleophilic and aromatic amino acids, such as serine, phenylalanine or tyrosine.