Synthesis of the H-phosphonate dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide and the phospha-Michael addition to unsaturated compounds

Abstract A series of phosphonate-containing compounds based on dibenzo[ d,f ][1,3,2]dioxaphosphepine 6-oxide (BPPO) is presented. BPPO is synthesized by a three–component condensation and is added to activated alkenes with systematically varied structure via phospha-Michael addition. Acrylates, α,β-unsaturated carboxylic acid diesters and benzoquinone are used as activated alkenes. The new compounds are characterized by 1 H, 13 C and 31 P NMR spectroscopy. The as-prepared phosphonates are envisioned to have flame retardant properties.