Total synthesis of new microbial sphingolipid type signaling molecules Sphingolipids are found in mammalian and bacterial membranes where they exert multiple intra and intercellular functions. Therefore binding partners of sphingolipids provide excellent targets for therapeutic approaches. Structurally related sulfonolipids (RIFs) are also of great interest for the interspecific interaction of Salpingoeca rosetta. In the present work new access routes to both classes of compounds are demonstrated by the means of total chemical synthesis. Using a hydrozirconation transmetallation reaction and a three step one pot reaction protection deprotection sequence several unnatural 2S 3S 6 hydroxy 4E sphingenin containing sphingolipids were prepared in only three (protected) or four (fully deprotected) consecutive synthetic steps. Among them is a fluorescently labeled derivative suitable for future biological studies. Furthermore the first total synthesis of two RIF 2 diastereomers and one congener is reported using 15 and eight synthetic steps respectively. A decarboxylative cross coupling reaction is used to synthesize the required branched alpha hydroxy fatty acids. Furthermore three different strategies are discussed in terms of their suitability for the synthesis of sulfonolipids: 1) the cysteine strategy which uses cysteine as the central building block; 2) the thioligation strategy which provides for a reaction similar to native chemical ligation to generate the peptide bond; and 3) the late stage strategy which provides for the introduction of sulfur at the end of the total synthesis. Finally the synthetic compounds are compared to the natural isolates in terms of their properties.