Synthesis of functionalized benzene using Diels–Alder reaction of activated acetylenes with synthesized phosphoryl-2-oxo-2H-pyran

An effective one-pot synthesis of benzene derivatives using a Diels–Alder reaction of activated acetylenes with phosphoryl-2-oxo-2 -pyrans is described. The latter compounds were synthesized in good yield the reaction of dialkyl acetylenedicarboxylates and alkyl bromides in the presence of trialkyl phosphites under solvent-free conditions at 50 C.