Self-catalytic Michael reaction of enolizable carbonyl compounds. A facile route to α-methylene-δ-valerolactones

Various dicyclohexylammonium 2-phosphono-5-oxoalkanoates were prepared by the Michael reaction of enolizable carbonyl compounds with the acrylate . The corresponding 2-phosphono-5-oxoalkanoic acids were converted into α-phosphono-δ-valerolactones . The products were shown to be useful substrates for the synthesis of α-methylene-δ-valerolactones by the Horner–Wadsworth–Emmons reaction.