Two new (-)-muricatacin mimics bearing a furano-furanone ring and an oxygenisostere in the side chain have been designed and synthesized and their in vitro antiproliferative activity was evaluated against several human tumour cell lines. Both analogues showed an increased activity against HL-60 cells with 17- and 185-fold higher potency than (-)-muricatacin. A straightforward synthesis of (-)-muricatacin