Hydroalkylation leading to heterocyclic compounds. Part 1: New strategies for the synthesis of polysubstituted 2H-pyran-2-ones

Polysubstituted 2H-pyran-2-ones and 5,6-dihydro-2H-pyran-2-ones were synthesized via the MCRs initiated by the hydroalkylation of alkynoates with activated methylenes. Under the optimized reaction conditions, the desired products were obtained in 47–88% isolated yields. The experimental results showed that the groups on activated methylenes act important roles in the nucleophilic attack fashion.