Compound 7

(3aS,5aR,6R,8aS,8bS)-6,8b-dimethyltetrahydro-1H-8a,5a-(epoxyethano)indeno[4,5-c]furan-3,4,10(3aH,5H)-trione

From: An eight-step gram-scale synthesis of (−)-jiadifenolide