Regiocontrolled palladium-catalyzed and copper-mediated C-H bond functionalization of protected L-histidine

We describe the controlled and regioselective transition-metal-catalyzed C-H bond arylation of protected L-histidine with aryl halides as the coupling partner. Using this approach, a large number of C-2 arylated L-histidines have been synthesized with diverse substitutions bearing electron-donating and electron-withdrawing groups, in good to excellent yields. These synthetic amino acids possessing dual hydrophobic-hydrophilic character are important synthons of bioactive peptidomimetics, which are imperative potent inhibitors of Cryptococcus neoformans.