title: Remote hydroxylation of methyl groups by regioselective cyclopalladation. Partial synthesis of hyptatic acid-A.
abstract: Hyptatic acid-A (32), a 2alpha,3beta,24-trihydroxyolean-12-en-28-oic acid, previously isolated from Hyptis capitata, was obtained from maslinic acid (2). The regioselective cyclopalladation of the axial methyl group on C-4 of maslinic acid afforded the C-24 hydroxymethylene group due to the presence of a C-2-OR substituent. Nevertheless, hederagenin (7) (23-hydroxy derivative) was formed when this oxygenated group was not present.
authors.affiliation: Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain.
authors.forename: Andrés
authors.initials: A
authors.lastname: García-Granados
authors.forename: Pilar E
authors.initials: PE
authors.lastname: López
authors.forename: Enrique
authors.initials: E
authors.lastname: Melguizo
authors.forename: Andrés
authors.initials: A
authors.lastname: Parra
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Simeó