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"Super armed" glycosyl donors: conformational arming of thioglycosides by silylation

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

Glycosyl donors protected with bulky silyl protective groups (tert-butyldimethylsilyl, TBS), on the 2-, 3- and 4-OH groups were found to have superior reactivity compared with benzylated thioglucosides. The enhanced reactivity is explained by the stereoelectronic effects associated with the conformational change induced by the silylation: A TBS silylated thioglucoside donor have axial OR groups while a benzylated thioglucoside have equatorial OR groups leading to much more favorable charge-dipole interactions in the transition state. This concept could be used to create ‘super armed' glucosyl, mannosyl, rhamnosyl and galactosyl donors, which could cross couple with the armed acceptors phenyl 2,3,4-tri-O-benzyl-ß-D-thioglucoside or phenyl 2,3,6-tri-O-benzyl-ß-D-thioglucoside to give the corresponding armed disaccharides in good to excellent yields.
OriginalsprogEngelsk
TidsskriftJournal of the American Chemical Society
Vol/bind129
Udgave nummer29
Sider (fra-til)9222-9235
Antal sider14
ISSN0002-7863
DOI
StatusUdgivet - 2007
Eksternt udgivetJa

ID: 2014591