Coumarins are an important class of natural heterocyclic compounds that have attracted considerable synthetic and pharmacological interest due to their various biological activities. This review emphasizes on the synthetic methods for the preparation of dialkyl 2-oxo-2H-1-benzo- pyran-3-phosphonates and alkyl 1,2-benzoxaphosphorin-3-carboxylates. Their chemical properties as acceptors in conjugate addition reactions, [2+2] and [3+2] cycloaddition reactions are discussed.
Keywords: 1,2-bezoxaphosphorines; 1,2-bezoxaphosphorines-3-phosphonic acid; 1,2-phosphorinines; 2-oxo-2H-1-benzopyrans; 2-oxo-2H-chromenes; [2+2] cycloaddition; [3+2] cycloaddition; conjugate addition; coumarins.