I have posted two reactions below. The top reaction is well known and occurs readily and near quantitatively (e.g. in protein modification), while the bottom reaction to my knowledge does not exist in the literature, but would be valuable to me. I would like to ask the experienced organic chemists out there if you think 2 and 4 will have similar reactivities with 1, or whether the phosphonate moeity will cause trouble or reduce reactiveness (resonance stabilization or side reactions?).
Forgot to add it to the image, but I normally run the top reaction in dichloromethane at a little above 0 C, with N-hydroxysuccinimide produced as a by-product.
Note: I currently don't have the time/resources to test this, but plan to in the future if I think it will work.