RESUMO
Reaction of a lithiated dithiinyl reagent with a O-perbenzylated D-glycono-delta-lactone readily generates the corresponding masked C-vinyl galactosides in high yields and full beta-selectivity. Removal of the sulfur mask renders the free vinyl aglycone with the vinyl group in either the Z or E configuration, depending on the desulfurization conditions chosen.
Assuntos
Galactose/análogos & derivados , Compostos de Vinila/síntese química , Configuração de Carboidratos , Galactose/química , Compostos Heterocíclicos/química , Lítio/química , Espectroscopia de Ressonância Magnética , Conformação Molecular , Estrutura Molecular , Oligossacarídeos/química , Antígeno Sialil Lewis X , Estereoisomerismo , Açúcares Ácidos/química , Compostos de Vinila/químicaRESUMO
4-Deoxy-l-hexoses were synthesized starting from our previously reported reagent 1 and (R)-benzyl glycidyl ether, which led in few steps to a substituted dihydropyran 6. The stereocontrolled hydroxylation of the latter afforded the corresponding 4-deoxy-l-hexoses 7a, 9, and 11. The same procedure, starting from (S)-benzyl glycidyl ether, enabled the preparation of their d-series enantiomers.