Spontaneous copolymerization of 1,3-dehydroadamantane

Copolymerizations of 1,3-dehydroadamantane, 1, and various vinyl monomers were carried out in THF at room temperature. On mixing of 1 with electron-deficient vinyl monomers such as acrylonitrile and methyl acrylate in the absence of initiator, the copolymerization spontaneously proceeded to give alternating copolymers in 28-88% yields. By contrast, no reaction of 1 occurred at all, when isobutyl vinyl ether or styrene was mixed under the similar conditions. These results indicate the high electron density of a central ó-bond in a strained [3.3.i]propellane derivative, 1. Alternating sequences of the resulting copolymers were characterized by NMR and MALDI-TOF-MS measurements. DSC and TGA measurements revealed the high thermal stability of the alternating copolymers containing bulky, stiff, and strain-free adamantane skeletons.