Straightforward synthesis towards mono and bis-phosphonic acid functionalised β-cyclodextrins

For the first time a novel class of cyclodextrins bearing phosphonic acid groups has been revealed using a new versatile methodology. These derivatives can be easily synthesised in four easy steps starting from the diol with relatively high percentage yields and no difficult purification procedures. Chemical modifications were carried out in a controlled regioselective manner using a DIBAL promoted de-O-benzylation, followed by a modified Horner-Wadsworth-Emmons reaction to introduce the key phosphorus moieties. Fully deprotected products could have wide applications as useful tools in biological systems as well as key building blocks in complex cyclodextrin chemistry.