Using a sultone as the key intermediate, the first enantioselective total synthesis of the antileukemic 1,10‐seco‐eudesmanolides (–)‐eriolanin (1) and (–)‐eriolangin (2) was achieved, which also established the hitherto unknown absolute configuration of these sesquiterpene lactones. Starting from 2‐bromo‐1‐(2‐furyl)ethanone, 24 steps were required to generate the common basic structure and two additional steps in each case for completion of the natural products. The effect of 1 and 2 on the cell cycle of human leukemia (HL‐60) cells was investigated by flow cytometry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)