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Significant Substituent Effect on the Anomerization of Pyranosides: Mechanism of Anomerization and Synthesis of a 1,2‐ cis Glucosamine Oligomer from the 1,2‐ trans Anomer
Author(s) -
Manabe Shino,
Satoh Hiroko,
Hutter Jürg,
Lüthi Hans Peter,
Laino Teodoro,
Ito Yukishige
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201303474
Subject(s) - chemistry , substituent , anomer , glycosidic bond , reactivity (psychology) , carbamate , medicinal chemistry , stereochemistry , organic chemistry , medicine , alternative medicine , pathology , enzyme
Abstract Aminoglycosides containing a 2,3‐ trans carbamate group easily undergo anomerization from the 1,2‐ trans glycoside to the 1,2‐ cis isomer under mild acidic conditions. The N‐substituent of the carbamate has a significant effect on the anomerization reaction; in particular, an N ‐acetyl group facilitated rapid and complete α‐anomerization. The differences in reactivity due to the various N‐substituents were supported by the results of DFT calculations; the orientation of the acetyl carbonyl group close to the anomeric position was found to contribute significantly to the directing of the anomerization reaction. By exploiting this reaction, oligoaminoglycosides with multiple 1,2‐ cis glycosidic bonds were generated from 1,2‐ trans glycosides in a one‐step process.