Inter- and intramolecular Horner–Wadsworth–Emmons reactions of 5-(diethoxyphosphoryl)-1-acyl-2-alkyl(aryl)-2,3-dihydro-4-pyridones

Dihydropyridones of the type 1 were converted to their C-5 alkylidene derivatives 2 by a reaction sequence involving phosphorylation, conjugate reduction or addition to provide piperidones 4, and then olefination via a Horner–Wadsworth–Emmons reaction. An intramolecular version of this method was used to prepare trans-bicyclic enone 13.