Cyclopolymerization of 1,2:5,6-Dianhydrohexitol Leading to A Novel Polymeric Carbohydrate

Abstract

Cyclopolymerization of 1,2:5,6-dianhydrohexitol has been studied in terms of regio- and stereoselectivity. The anionic cyclopolymerizations of 1,2:5,6-dianhydro-D-mannitol and 1,2:5,6-dianhydro- L-iditol produced (1→6)- and (6→1)-2,5-anhydro-D-glucitol, respectively. On the other hand, the cyclopolymerizations using a cationic initiator gave the polymer consisting of 2,5-anhydro-D-glucitol as the cyclic constitutional unit along with 1,6:2,5-dianhydro-D-glucitol as a by-product. For the cationic cyclopolymerization of 1,2:5,6-dianhydro-D-glucitol, the resulting polymer was confirmed to have the constitutional unit mainly of 2,5-anhydro-D-mannitol, while the polymer obtained using anionic initiator consisted of two cyclic repeating units, 2,5-anhydro-D-mannitol unit and 2,5-anhydro-L-iditol unit. The cyclopolymerization of 1,2:5,6-dianhydrohexitol was regio- and stereoselective, i.e., the intramolecular cyclization proceeded through the α-scission with inversion of the configuration at the α-carbon and the intermolecular propagation through the β-scission with retention. The polymer consisting of 2,5-anhydrohexitol, a novel polymeric carbohydrate, showed a metal cation- binding ability and a chiral recognition property toward the racemic amino acid derivatives.