Stereoselective glycosylations using oxathiane spiroketal glycosyl donors.
Novel oxathiane spiroketal donors have been synthesised and activated via an umpolung S-arylation strategy using 1,3,5-trimethoxybenzene and 1,3-dimethoxybenzene. The comparative reactivity of the resulting 2,4,6-trimethoxyphenyl (TMP)- and 2,4-dimethoxyphenyl (DMP)-oxathiane spiroketal sulfonium ions is discussed, and their α-stereoselectivity in glycosylation reactions is compared to the analogous TMP- and DMP-sulfonium ions derived from an oxathiane glycosyl donor bearing a methyl ketal group. The results show that the stereoselectivity of the oxathiane glycosyl donors is dependent on the structure of the ketal group and reactivity can be tuned by varying the substituent on the sulfonium ion.
School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
Martin A
MA
Fascione
Nicola J
NJ
Webb
Colin A
CA
Kilner
Stuart L
SL
Warriner
W Bruce
WB
Turnbull
D000840:Anisoles / Q000737:chemistry; D018360:Crystallography, X-Ray; D005663:Furans / Q000737:chemistry*; D006027:Glycosides / Q000138:chemical synthesis*; D006031:Glycosylation; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010696:Phloroglucinol / Q000031:analogs & derivatives / Q000737:chemistry; D013141:Spiro Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013452:Sulfonium Compounds / Q000737:chemistry; D013865:Thioglycosides / Q000138:chemical synthesis*
D000840:Anisoles; D005663:Furans; D006027:Glycosides; D006573:Heterocyclic Compounds, 1-Ring; D013141:Spiro Compounds; D013452:Sulfonium Compounds; D013865:Thioglycosides; C517814:oxathiane; C520774:spiroketal; C015560:1,3,5-trimethoxybenzene; C031201:1,3-dimethoxybenzene; D010696:Phloroglucinol