Abstract

Rhodium(III)-catalyzed C-H activation has been widely employed for the construction of heterocycles. In 2013, the first oxazolinium was made through rhodium(III)-catalyzed cyclization. Given the electrophilic properties of the oxazoliniums, nucleophilic attack on the oxazoline ring could lead to the formation of isoquinolones. Despite the advancement of oxazoline ring-opening studies, research on application of oxazoliniums in bioconjugation is still limited. In 2019, our group reported an efficient bioconjugation of peptides and proteins using in situ-generated isoxazoliniums with excellent chemoselectivity at the cysteine residue. To explore the potential of oxazoliniums as a peptide modification reagent, here we present rhodium(III)-catalyzed synthesis of oxazoliniums and cysteine-selective modification using oxazoliniums. 

Reference:

1. Deng, J.-R.; Chung, S.-F.; Leung, A. S.-L.; Yip, W.-M.; Yang, B.; Choi, M.-C.; Cui, J.-F.; Kung, K. K.-Y.; Zhang, Z.; Lo, K.-W.; Leung Y.-C.; Wong, M.-K. Communications Chemistry, 2019, 2, 93.