A 9,13-epoxylabdane from Colophospermum mopane

Abstract A new diterpene, 8(S),13(S)-dihydrogrindelic acid ( 2 ) was isolated from the seeds of Colophospermum mopane along with its previously described C-13 epimer ( 1 ). The structure of 2 was established primarily by NMR which required some revisions on the NMR shift assignments of 1 . The importance of 1 and 2 as the missing links in the biosynthesis of 9,13-epoxylabdanes is briefly discussed.