Lathyranoic Acid A: First Secolathyrane Diterpenoid in Nature from Euphorbia lathyris

Lathyranoic acid A (1), the first secolathyrane diterpenoid with an unprecedented skeleton, and a new diterpenoid Euphorbia factor L11 (2) were isolated from the seeds of Euphorbia lathyris. Their structures were elucidated by spectroscopic analysis and chemical methods. A biogenetic route involving an enzymatic Baeyer−Villiger oxidation as the key step was postulated for the transformation of 2 to 1 and mimicked by an unusual chemical Baeyer−Villiger oxidation.