Its hard to understand what you're asking, or at least why you're asking it. But we'll try to figure it out.
You want to de-toxify poison ivy in situ, that's easy to understand, and you've looked up the structure, and the organic chemistry involved. That's nice work. But then what's the plan? Won't any reagent you can think of damage the plant? Or other components the plant needs? Plants don't have a circulatory system, water travels from roots to leaves in a one-way trip (mostly,) so your chemical won't always work.
Step one, id the plants, and then, instead of putting on gloves and yanking it out, or spraying it with herbicide from a distance, you carefully approach and inject ... something, that does ... something. Now what, we have a lovely shiny vine growing that doesn't cause contact dermatitis? We have other species that already are like that. Do you want to genetically engineer poison ivy that doesn't make urushiol? Again, what for?