Polymerization of cyclic monomers 9. Synthesis and radical polymerization of spirocyclic 2-vinylcyclopropanes

6,6-Diethyl- (1a) and 6-methyl-6-propyl-5, 7-dioxa-4,8-dioxo-1-vinylspiro[2 .5]octane (1b) were synthesized by the acetalization of 2-vinylcyclopropane -1,1-dicarrboxylic acid with 2- or 3-pentanone. The new monomers were chara cterized by IR, H-1 NMR and C-13 NMR spectroscopy. The radical polymerizati on of the monomers 1a and 1b, in addition of 6,6-methyl-5,7-dioxa-4,8-dioxo -1-vinylspiro[2.5]octane (1c) and (exo/endo) >7-ethoxycarbonyl-2-oxo-7-viny l-biocyclo[4.1.0]-heptane (1d), was carried out in bulk with 2,2'-azoisobut yronitrile (AIBN) as the initiator. The polymer yield with Id was only low. The polymerization of the monomers 1a and 1c resulted in cross-linked poly mers, whereas in case of the polymerization of monomer Ib soluble polymers in a high yield were obtained.