8-methoxy-3,3,11,11-tetramethyl-13-(3-methylbut-2-en-1-yl)-1-(3-methylpenta-2,4-dien-1-yl)-3,3a,4,5-tetrahydro-7H,11H-1,5-methanofuro[3,4-g]pyrano[3,2-b]xanthene-7,15-dione