Regio- and stereoselective cyclopolymerization of 1,2:5,6-dianhydro-3,4-di-O-methyl-D-glucitol leading to polymers with 2,5-anhydro-3,4-di-O-methyl-D-mannitol and/or -L-iditol units

The cyclopolymerization of 1,2 :5,6-dianhydro-3.4-di-O-methyl-D-glucitol was carried out using cationic and anionic catalysts. The polymerizations proceeded homogeneously up to high conversion and gave linear polymers without formation of gel. For the cationic cyclopolymerizations using BF 3 .OEt 2 and SnCl 4 , the resulting polymer was confirmed to have the constitutional unit mainly of 2,5-anhydro-3,4-di-O-methyl-D-mannitol by comparing its 13 C NMR spectrum with that of 2,5-anhydro-1,3,4,6-tetra-O-methyl-D-mannitol. For anionic cyclopolymerization using t-BuOK, the obtained polymer consisted of two cyclic repeating units, 2,5-anhydro-3.4-di-O-methyl-D-mannitol and 2,5-anhydro-3,4-di-O-methyl-L-iditol. For the regio- and stereoselective polymerizations, intra- and intermolecular reactions introduced α- and β-scissions of the epoxides with inversion and retention of the configuration at the α-carbon, respectively.