Living Anionic Polymerization of Benzofulvene: Highly Reactive Fixed Transoid 1,3-Diene

Yuki Kosaka; Keita Kitazawa; Sotaro Inomata; Takashi Ishizone

doi:10.1021/mz4000078

Living Anionic Polymerization of Benzofulvene: Highly Reactive Fixed Transoid 1,3-Diene

ACS Macro Lett. 2013 Feb 19;2(2):164-167. doi: 10.1021/mz4000078. Epub 2013 Feb 4.

Authors

Yuki Kosaka¹, Keita Kitazawa¹, Sotaro Inomata¹, Takashi Ishizone¹

Affiliation

¹ Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1-S1-13 Ohokayama, Meguro-ku, Tokyo 152-8552, Japan.

PMID: 35581780
DOI: 10.1021/mz4000078

Abstract

Anionic polymerization of benzofulvene (BF, α-methyleneindene), an exomethylene monomer having a fixed transoid 1,3-diene moiety, quantitatively proceeded with sec-BuLi or diphenylmethylpotassium in THF at -78 °C for 1 h. The resulting poly(BF)s possessed the predicted molecular weights based on the molar ratios between monomer and initiators and narrow molecular weight distributions (M_w/M_n = 1.1). High anionic polymerizability of BF was realized by the fact that a well-defined diblock copolymer, poly(methyl methacrylate)-block-poly(BF), was obtained by the sequential copolymerization of BF with a low nucleophilic enolate anion of living poly(methyl methacrylate) in quantitative efficiency. NMR analyses indicated that the repeating units of poly(BF) consisted of a 1,2-addition unit (41%) and a 1,4-addition unit (59%) without a 3,4-addition unit, suggesting that the exomethylene group of BF always participated in the polymerization. Thus, BF acted as a novel polymerizable transoid 1,3-diene in the anionic polymerization.