Developing an asymmetric, stereodivergent route to selected 6-deoxy-6-fluoro-hexoses.
Free radical bromination and nucleophilic fluorination allows the conversion of methyl sorbate into the 6-fluoro analogue which undergoes sequential asymmetric dihydroxylation reactions. A range of 6-deoxy-6-fluorosugars were prepared by using different combinations of ligands. While the enantiomeric excesses obtained were comparable to those from other 6-substituted sorbates, the regioselectivity of dihydroxylation was moderate, with both 2,3- and 4,5-diols being obtained. A successful temporary persilylation strategy was evolved to convert the products of dihydroxylation rapidly to the fluorosugars 6-deoxy-6-fluoro-L-idose, 6-fluoro-L-fucose and 6-deoxy-6-fluoro-D-galactose, which were obtained in overall yields of 4%, 6% and 8% from methyl 6-fluoro-hexa-2E,4E-dienoate .
Caravano
Audrey
A
Department of Chemistry, University of Leicester, University Road, Leicester LE17RH, UK.
Field
Robert A
RA
Percy
Jonathan M
JM
Rinaudo
Giuseppe
G
Roig
Ricard
R
Singh
Kuldip
K
D005643:Fucose / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D006601:Hexoses / Q000138:chemical synthesis*; D006900:Hydroxylation
D006601:Hexoses; C010997:idose; D005643:Fucose; C037333:6-deoxy-6-fluorogalactose