AUTHOR=Qiu Li-Jun , Liu Dan , Zheng Ke , Zhang Ming-Tao , Zhang Chi 

TITLE=A Benziodoxole-Based Hypervalent Iodine(III) Compound Functioning as a Peptide Coupling Reagent

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00183

DOI=10.3389/fchem.2020.00183

ISSN=2296-2646

ABSTRACT=<p>1-Benzoyloxy-1,2-benziodoxol-3-(1H)-one (IBA-OBz), a readily available and bench stable benziodoxole-based iodine(III) reagent, can be employed for the synthesis of dipeptides from various standard and sterically hindered amino acids in the presence of (4-MeOC<sub>6</sub>H<sub>4</sub>)<sub>3</sub>P. The combined system of IBA-OBz/(4-MeOC<sub>6</sub>H<sub>4</sub>)<sub>3</sub>P is also successfully applied to the solid-phase peptide synthesis and a pentapeptide leu-enkephalin in unprotected form has been synthesized. Density functional theory calculations reveal that the rate-limiting step is nucleophilic attack of 4-dimethylaminopyridine (DMAP) onto IBA-OBz.</p>