SYNTHESIS AND POLYMERIZATION BEHAVIOR OF 2,3-DIHYDRO-1,4-DIOXIN-2-ONEAND ITS 3-METHYL DERIVATIVE

The hitherto unknown 2,3-dihydro-1,4-dioxin-2-one (7) and its 3-methyl derivative 8 have been synthesized for the first time. The olefinic d ouble bond is inserted into the saturated 1,4-dioxanone precursors 3 a nd 6 a/b by a retro-Diels-Alder reaction in the last step of the synth esis The 1,4-dioxanone systems of 3 and 6 are prepared by reacting a v icinal dialkoxide with alpha-halogenated acyl halides, thus forming th e ester and the ether bond in a one-pot reaction. Monomers 7 and 8 are polymerized by cationic initiation. The resulting products undergo fr agmentation to form oligomers in the presence of protic solvents, indi cating that ring-opening polymerization of the delta-lactone apparentl y leads to polyester chain segments.