Facile Synthesis of Oleanane‐type Pentacyclic Triterpenoids Bearing Hydroxy Groups on D/E Rings

Abstract Pentacyclic triterpenoids (PTs) comprise one of the largest class of natural products; many bear higher oxidation state on the D/E rings and exhibit a wide range of biological activities. Here, we report the chemical synthesis of a series of oleanane‐type PTs bearing hydroxy groups on D/E rings from the largely available oleanolic acid by transformations following site‐selective C−H hydroxylation.