The synthesis of the slime mold pigments arcyroxocin A and B is described. The key step in the synthesis is the oxidative ring closure of an N-protected 3-(4-hydroxyindol-3-yl)-4-indol-3-ylmaleimide with DDQ/PPTS, which affords exclusively the desired arcyroxocin derivative. Attempts to obtain the arcyroxocin system from a 3-(4-hydroxyindolyl)-4-(2-oxoindolinyl)maleimide precursor were less successful