3,4-Dichloro-2(5H)-furanone, which has been prepared efficiently from mucochloric acid, has been transformed selectively into 4-aryl-3-chloro-2(5H)-furanones either by Suzuki- Stille-type reactions. These monochloro derivatives have been used as precursors either to (Z)-4-aryl-5-[1-(aryl)methylidene]-3-chloro-2(5H)-furanones, including naturally occurring rubrolide M, or to unsymmetrical 3,4-diaryl-2(5H)-furanones. Some 2(5H)-furanone derivatives so prepared have been found to exhibit significant cytotoxic activity in vitro against the NCI three-cell-line panel, but limited cytotoxicity against the NCI human tumor 60 cell-line panel. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).