Syntheses and utilizations of pyrroline and tetrahydropyridine nitroxide-based phosphonate esters, a phosphate ester and a bisphosphonate

Five- and six-membered cyclic nitroxide-based allylic phosphonate esters, α-ketophosphonate esters were obtained from the corresponding paramagnetic allyl bromides and acyl chlorides respectively via the Arbuzov reactions. The α-hydroxyphosphonate esters were accessed by Pudovik reactions from the corresponding paramagnetic ketones and aldehydes. The β-ketophosphonate esters were obtained from the appropriate 1-alkynylphosphonate esters via PdCl2-catalyzed hydration. The synthesis of an allylic phosphate ester and a paramagnetic geminal bisphosphonate was also reported.