Stereospecific Anionic Polymerization of [alpha]-(Hydroxymethyl)acrylate with Protective Group

• Published in: Macromolecular symposia. Vol. 350; no. 1; p. 86
• Main Authors: Kohsaka, Yasuhiro, Suzawa, Kazuha, Kitayama, Tatsuki
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.04.2015
• ISSN: 1521-3900
• DOI: 10.1002/masy.201400028

Summary Anionic polymerizations of hydroxyl-protected [alpha]-(hydroxymethyl)acrylates were investigated. The methyl ester with methoxymethyl (1-MOM) and allyl (1-allyl) protecting groups were polymerized by isopropyl [alpha]-lithioisobutyrate (Li-iPrIB) in toluene at -78°C, affording highly isotactic polymers. Similarly, the polymerization of ethyl ester (2-MOM) gave an isotactic polymer, while those of t-butyl (3-MOM) and isobutyl (4-MOM) ester did not form any polymeric products. The hydrolysis of poly(2-MOM) in acidic conditions resulted in the deprotection of MOM group, although the acid also catalyzed the ester exchange between the neighboring units to form lactone units, as observed by 1H NMR analysis, IR spectroscopy and thermogravimetric analysis. A film of poly(2-MOM) exposed to HCl vapor for 2h became insoluble in any organic solvents due to the lactonization in solid state.