Glycosyl Fluorides as Intermediates in BF3·OEt2‐Promoted Glycosylation with Trichloroacetimidates. Issue 9 (8th March 2017)

• Record Type: Journal Article
• Authors: Nielsen, Michael M.; Stougaard, Bolette A.; Bols, Mikael; Glibstrup, Emil; Pedersen, Christian M.
• Is Part Of: European journal of organic chemistry. Issue 9(2017)
• Page Start: 1281
• Page End: 1284
• Publication Date: 2017-03-08
• Subjects: Glycosylation -- Reaction mechanisms -- Glycosides -- NMR spectroscopy -- Trichloroacetimidates; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201601439
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : Glycosyl fluorides have been found to be important intermediates in glycosylations with trichloroacetimidate donors and BF3 · OEt2 activation (0.2–1 equiv.). Low‐temperature NMR spectroscopy experiments revealed that the α‐trichloroacetimidate was transformed into the glycosyl fluoride with inversion of stereochemistry, whereas the β anomer was not. A concerted mechanism was suggested for the stereospecific formation of glycosyl fluorides, which is not accounted for in the classic mechanism. Abstract : Glycosyl fluorides are important intermediates in glycosylations with trichloroacetimidate (TCA) donors and BF3 · OEt2 activation. Low‐temperature NMR spectroscopy experiments reveal that the α‐TCA is transformed into the glycosyl fluoride with inversion of stereochemistry, whereas the β anomer is not.