Anionic Cyclopolymerization of 1,2:5,6-Dianhydro-3,4-di-O-methyl-l-iditol Leading to (6→1)-2,5-Anhydro-3,4-di-O-methyl-d-glucitol

Abstract

The anionic cyclopolymerization of 1,2:5,6-dianhydro-3,4-di-O-methyl-L-iditol (3) was carried out using t-BuOK and KOH. The resulting polymer 4 consisted of 2,5-anhydro-3,4-di-O-methyl-D-glucitol as a five-membered repeating unit, which was identical with that of polymer 2 obtained from 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (1). The copolymerization of 1 with 3 produced a random copolymer consisting of (1f6)-, (6f1)-, (1f1)-, and (6f6)-linked 2,5-anhydro-3,4-di-O-methyl-D-glucitol. These facts elucidated the presence of two linkages during the homopolymerization of 1 and 3, i.e., the (1f6) and (6f1)-bonded 2,5-anhydro-3,4-di-O-methyl-D-glucitol units in polymers 2 and 4, respectively.

Synthesis of Hyperbranched Carbohydrate Polymers by Ring‐Opening Multibranching Polymerization of Anhydro Sugar

“…However, the polymer obtained was mostly insoluble along with a small amount of a water-soluble polymer, which was quite different from the anionic cyclopolymerization of 3,4-di-O-alkyl-1,2:5,6-dianhydro-D-mannitol leading to gel-free polymers. [57][58][59][60] In the 1 H NMR spectrum of the polymer prepared by the anionic polymerization, the signal was broad and a resonance characteristic of the epoxy protons was observed. Although the extent of the cyclization ( f c ) of the water-soluble polymer was 0.9, the polymer gradually became insoluble after storage for a few days.…”

Regio- and Stereoselective Cyclopolymerization of 1,2:5,6-Dianhydroallitol and 1,2:5,6-Dianhydrogalactitol Leading to a Novel Carbohydrate Polymer of (2→6)-1,5-Anhydro-dl-galactitol

“…The low value at the ratio of 20 suggests some participation of the chain transfer to the monomer similar to that found in the case of 1,2:5,6-dianhydro-3,4-di-O-methyl-L-iditol (6) and D-glucitol (7). 8,9 The chain transfer, which forms an allyl oxideinitiating moiety through the E2 mechanism (Scheme 2), satisfies the requirement of trans elimination in the configurations of 3, 6, and 7, but not in the configurations of 1 and 5. 10,12 The anionic polymerization of 1 in THF had the same character as that in toluene.…”

Regio- and stereoselective cyclizations of dianhydro sugar alcohols catalyzed by a chiral (salen)CoIII complex

“…Structures for 1-5. O-methyl-D D-glucitol (12) in 57.2%, 27.9%, and 5.9% yields, respectively, as shown in Table 2 and Scheme 3. On the contrary, when (S,S)-1 was used, no product was obtained and unreacted 3 was recovered.…”

“…1.6. 2,5-Anhydro-3,4-di-O-methyl-D D-glucitol (10), 1,6-anhydro-3,4-di-O-methyl-D D-mannitol (11) and 1,6:2,5-dianhydro-3,4-di-O-methyl-D D-glucitol (12) Compounds 10-12 were obtained by the hydration of 3 with (R,R)-1 after 3 h at rt. After removing the catalyst, the products were purified by column chromatography using EtOAc/acetone (1/1) as the eluant.…”

“…[1][2][3][4][5][6][7][8] In particular, regio-and stereoselective cyclizations of dianhydro sugars, such as 1,2:5,6-dianhydrohexitols and 1,2:4,5-dianhydropentitols, are an interesting approach for the stereocontrolled synthesis of carbohydrate derivatives. [9][10][11][12][13][14][15][16] For example, Kuszmann reported that the regio-and stereoselective cyclizations of 3,4-di-O-alkyl-1,2:5,6-dianhydro-D D-mannitol and 3,4-di-O-alkyl-1,2:5,6-dianhydro-L L-iditol with hydrogen bromide produced the corresponding 2,5-anhydro-6-bromo-6-deoxy-D D-glucitol and 2,5-anhydro-1-bromo-1-deoxy-D D-glucitol, respectively. 9 In addition, we reported that the asymmetric cyclization of meso-1,2:5,6-dianhydrohexitols and meso-1,2:4,5-dianhydropentitols using chiral (salen)Co III Ac ((R,R)-1 and (S,S)-1) led to chiral anhydroalditol alcohols in extremely high enantiomeric excesses.…”