Bifunctional Building Blocks for Glyco-Architectures by TiCl4-Promoted Ring Opening of Cyclodextrin Derivatives
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- 作者：Andreas Bö ; sch ; Petra Mischnick
- 刊名：Biomacromolecules
- 出版年：2007
- 出版时间：July 2007
- 年：2007
- 卷：8
- 期：7
- 页码：2311 - 2320
- 全文大小：194K
- 年卷期：v.8,no.7(July 2007)
- ISSN：1526-4602
文摘
During our studies on the preparation of blocklike substituted 1,4-glucans by cationic ring-opening polymerization,1,2we found that TiCl4 behaves differently from common initiators like Et3O+X- (X = PF6, SbCl6), BF3·Et2O, ormethyl triflate, causing only ring opening under formation of 
chars/alpha.gif" BORDER=0>-maltooligosyl chlorides bearing one free hydroxylgroup (4-OH) at the nonreducing end. These compounds are valuable building blocks for the preparation of newglyco-architectures since they are easily accessible starting materials for direct glycosylations or the preparationof a variety of oligomeric glycosyl donors like alkyl glycosides, thioglycosides, or azides. We successfully carriedout and optimized the TiCl4-promoted ring opening with per-O-methylated, per-O-ethylated, and temporarilyprotected per-O-allylated cyclodextrins of various ring size. 1H NMR spectroscopy and high-pressure liquidchromatography-evaporative light-scattering detection (HPLC-ELSD) were used to characterize the products.
chars/alpha.gif" BORDER=0>-maltooligosyl chlorides bearing one free hydroxylgroup (4-OH) at the nonreducing end. These compounds are valuable building blocks for the preparation of newglyco-architectures since they are easily accessible starting materials for direct glycosylations or the preparationof a variety of oligomeric glycosyl donors like alkyl glycosides, thioglycosides, or azides. We successfully carriedout and optimized the TiCl4-promoted ring opening with per-O-methylated, per-O-ethylated, and temporarilyprotected per-O-allylated cyclodextrins of various ring size. 1H NMR spectroscopy and high-pressure liquidchromatography-evaporative light-scattering detection (HPLC-ELSD) were used to characterize the products.