Seleno‐Michael Reaction of Stable Functionalised Alkyl Selenols: A Versatile Tool for the Synthesis of Acyclic and Cyclic Unsymmetrical Alkyl and Vinyl Selenides

Abstract

AbstractSeleno‐Michael additions of stable functionalised primary alkyl selenols to activated alkenes and alkynes are described. In the presence of Al2O3, β‐hydroxy‐, β‐amino‐, and β‐mercapto selenols react smoothly with electron‐poor alkenes and alkynes to afford the corresponding unsymmetrical functionalised dialkyl‐ and alkyl−vinyl‐selenides in good yield. The very mild conditions allow a broad range of selenols and Michael acceptors to be converted into the corresponding synthetically valuable seleno‐Michael adducts, demonstrating high selectivity and excellent functional group tolerance. Hydroxy‐ and mercapto‐substituted vinyl selenides were efficiently employed for the synthesis of functionalised 1,3‐oxaselenolanes, 1,3‐thiaselenolanes, and 1,4‐thiaselenanes through intramolecular oxa‐ and thia‐Michael additions. Furthermore, a NaH‐promoted lactonization enables the synthesis of variously substituted 2‐oxo‐1,4‐oxaselenanes from hydroxy−vinyl‐selenides. Evaluation of thiol peroxidase‐like properties of novel functionalised organoselenides demonstrated that they possess a remarkable catalytic antioxidant activity.magnified image