In a recent article2 we presented complete stereochemical expressions for several sesquiterpene lactones from Ti-thonia diuersifolia Hemsl., viz., tagitinin A, B (= deacetylwoodhousin), C, D (= tirotundin), and E, 3, 4 as well as for some other related compounds. Since formulation of tagitinin E as the heliangolide 1 was based entirely on
![(1aR,5aS,9R,10aR,Z)-4,10a-dimethyl-8-(morpholinomethyl)-3,7-dioxo-1a,2,3,5a,7,8,8a,9,10,10a-decahydrooxireno[2',3':5,6]cyclodeca[1,2-b]furan-9-yl isobutyrate结构式](https://image.chemsrc.com/caspic/047/72301-74-7.png)
![(4R,6E,10Z,11aS)-6,10-dimethyl-3-methylene-2,9-dioxo-2,3,3a,4,5,8,9,11a-octahydrocyclodeca[b]furan-4-yl isobutyrate结构式](https://image.chemsrc.com/caspic/123/72301-72-5.png)
![(5aR,8aR,9R,Z)-4,10a-dimethyl-8-methylene-3,7-dioxo-1a,2,3,5a,7,8,8a,9,10,10a-decahydrooxireno[2',3':5,6]cyclodeca[1,2-b]furan-9-yl isobutyrate结构式](https://image.chemsrc.com/caspic/085/72301-73-6.png)
![(4R,6R,7E,10Z)-2,3,3aβ,4,5,6,9,11aα-Octahydro-3-methylene-6-hydroxy-2,9-dioxo-4-(2-methylpropanoyloxy)-6,10-dimethylcyclodeca[b]furan结构式](https://image.chemsrc.com/caspic/343/59979-56-5.png)
![(1aR,3S,5aS,9R,10aR,Z)-3-hydroxy-4,10a-dimethyl-8-(morpholinomethyl)-7-oxo-1a,2,3,5a,7,8,8a,9,10,10a-decahydrooxireno[2',3':5,6]cyclodeca[1,2-b]furan-9-yl isobutyrate结构式](https://image.chemsrc.com/caspic/009/72301-75-8.png)