“…Pentacyclic triterpenes (PTs) are bioactive natural products, which display a remarkable spectrum of biological activities, such as anti-tumor, anti-HIV, anti-microbial, anti-diabetic, and anti-inammatory activities. [1][2][3][4] The substitution of hydroxyl or carbonyl groups to the methyl or methenyl carbons, respectively, of the skeleton greatly enrich the structural diversity 2,5,6 and is also essential for the biological activities and structural modication of PTs. [7][8][9] Herein, the research on the structural modication of PTs was focused on the functionalization of the unactivated C-H bonds on the skeleton; it could also enrich the structural diversities and generate more effective and/or less toxic derivatives.…”