Heterocyclic derivative syntheses by palladium-catalyzed oxidative cyclization-alkoxycarbonylation of substituted gamma-oxoalkynes

The heterocyclic ring formation by means of PdI2-catalyzed oxidative cyclization-alkoxycarbonylation reactions to aliphatic acetylenic ketones is investigated. It is found that cyclopentenone, dihydropyridinone and tetrahydropyridinedione derivatives, formed when the reaction is carried out at higher temperature and for a long time, can also be selectively obtained through an acid treatment of tetrahydrofuran and oxazoline derivatives.