REGIOSELECTIVE 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 2,5-ANHYDRO-3,4-DI-O-METHYL-L-IDITOL UNITS/

The cyclopolymerization of 1,2:5,5-dianhydro-3,4-di-O-methyl-D-glucito l was carried out using cationic and anionic catalysts. The polymeriza tions proceeded homogeneously up to high conversion and gave linear po lymers without formation of gel. For the cationic cyclopolymerizations using BF3 . OEt(2) and SnCl4, the resulting polymer was confirmed to have the constitutional unit mainly of 2,5-anhydro-3,4-di-O-methyl-D-m annitol by comparing its C-13 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-methy l-L-iditol. For the regio-and stereoselective polymerizations, intra- and intemolecular reactions introduced alpha- and beta-scissions of th e epoxides with inversion and retention of the configuration at the al pha-carbon, respectively.