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A 3,4‐ trans ‐Fused Cyclic Protecting Group Facilitates α‐Selective Catalytic Synthesis of 2‐Deoxyglycosides
Author(s) -
Balmond Edward I.,
BenitoAlifonso David,
Coe Diane M.,
Alder Roger W.,
McGarrigle Eoghan M.,
Galan M. Carmen
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201403543
Subject(s) - selectivity , disiloxane , chemistry , catalysis , protecting group , anomer , glycoconjugate , combinatorial chemistry , stereochemistry , organic chemistry , alkyl , biochemistry
Abstract A practical approach has been developed to convert glucals and rhamnals into disaccharides or glycoconjugates with high α‐selectivity and yields (77–97 %) using a trans ‐fused cyclic 3,4‐O‐disiloxane protecting group and TsOH⋅H 2 O (1 mol %) as a catalyst. Control of the anomeric selectivity arises from conformational locking of the intermediate oxacarbenium cation. Glucals outperform rhamnals because the C6 side‐chain conformation augments the selectivity.