2- C-Methyl- d-erythritol 4-phosphate is a key intermediate in the mevalonate independent pathway for isoprenoid biosynthesis. In order to investigate the fate of the protons in this metabolic route, [3,5,5,5- 2H 4]-2- C-methyl- d-erythritol was synthesized. The relevant steps allowing deuterium introduction were a palladium(II)-catalyzed hydrostannation and a coupling reaction between a vinyl iodide and a methylcyanocuprate.