https://www.selleckchem.com/pr....oducts/cbr-470-1.htm
Pentacyclic triterpenoids (PTs) constitute one of the biggest families of natural products, many with higher oxidation state at the D/E rings possess a wide spectrum of biological activties but are poorly accessible. Here we report a site-selective C-H hydroxylation at the D/E rings of PTs paving a way toward these important natural products. We find that Schönecker and Baran's Cu-mediated aerobic oxidation can be applied and become site-selective on PT skeletons, as being effected unexpectedly by the chirality of the transient pyridi