Group-transfer copolymerization of cyclic trimethylsilyl dienolate with coumarin

This paper describes the group-transfer copolymerization of cyclic trimethylsilyl dienolate (1) with coumarin (4). The copolymerization took place in the presence of tetrabutylammonium benzoate as the catalyst to produce the branched copolymer 5 having two lactone units. The structure of the isolated copolymer was determined by the 1H NMR, 13C NMR, and IR spectra. The molecular weights were determined by GPC with DMF as eluent using polystyrene standards to be 6400–7900. The contents of coumarin units in the copolymers are higher than 50%, because of occurrence of homopropagation of 4.