Synthesis of β-hydroxy-α,β-unsaturated carbonyl compounds via the Morita–Baylis–Hillman reaction of paramagnetic aldehydes

Abstract To investigate the possibilities of carbon–carbon bond formation in the presence of nitroxides, a novel group of paramagnetic Morita–Baylis–Hillman adducts were synthesized from the reaction starting with five- and six-membered cyclic nitroxide aldehydes and various activated alkenes in the presence of a base, affording β -hydroxy- α , β -unsaturated carbonyls. These adducts could serve as valuable building blocks in nitroxide chemistry. To extend our study, a Morita–Baylis–Hillman alcohol was converted into an iodine derivative, a key intermediate for nucleophilic substitution, forming new cysteine and alkyne spin labels. Additionally, the paramagnetic acrylate adduct was transformed into a β -ketoester, which could be a starting material for synthesizing new heterocyclic compounds bearing a nitroxide moiety. Graphical abstract