Cacalolides from Senecio barba‐johannis

From the roots of Senecio barba‐johannis DC, the two new cacalolides 13‐acetoxycacalohastin (2) and 13‐hydroxy‐14‐oxocacalohastin (3), together with the known cacalolide 13‐acetoxy‐14‐oxocacalohastin (4) were isolated. Their structures were determined on the basis of chemical and spectroscopic evidence. Complete 1H and 13C NMR chemical shift assignments of these compounds were achieved using one‐ and two‐dimensional NMR methods, including gHMQC and gHMBC experiments.