Okay, now I have a bit better idea of what you're trying to synthesize. My next question is, what do you want the magnesium to do? As I said, you can make a Grignard reagent, but that's very reactive and won't survive another chemical step, it'll react with something. Are you trying to introduce magnesium to a receptor or protein and use threonine as the delivery system? Or is the magnesium just part of an intermediate that you will use for a future chemical step?