I am a research student currently exploring on how to synthesize water-soluble rotaxanes via Diels-Alder Reaction. But I have a problem what compound I should use as the stopper of the rotaxane.
My criteria for a stopper are :
1) It must be big/bulky (So the γ-cyclodextrin will not leave the rotaxane even after combining the Diene and the Dienophile via Diels-Alder Reaction)
2) It must have a hydroxyl group (This is because both of my diene and dienophile has a carboxylic acid group at end of it, and I would like to combine them with the stopper via esterification)
3) It must be hydrophilic.
I would greatly appreciate if you could attach any kinds of literature to your statement or other alternatives in creating the stopper.