One-step synthesis of non-anomeric sugar isothiocyanates from sugar azides.
Tandem Staudinger-aza-Wittig reaction of primary azidodeoxy sugars with triphenylphosphine-carbon disulfide affords the corresponding primary deoxyisothiocyanato sugars in high yield. No products arising from O --> N acyl migration or formation of dimeric carbodiimides were observed. Interestingly, a polymer-supported triarylphosphine can advantageously replace triphenylphosphine, thus limiting the purification step to a simple filtration process. The reaction also allows the preparation of 5-deoxy-5-isothiocyanato sugars, a hitherto unknown class of compounds, from the corresponding azide precursors. Secondary sugar azides bearing the azido group at an endocyclic carbon atom afforded much lower isothiocyanation yields under these reaction conditions.
García-Moreno
M Isabel
MI
Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, Aptdo 553, E-41071 Sevilla, Spain.
Díaz-Pérez
Paula
P
Benito
Juan M
JM
Ortiz Mellet
Carmen
C
Defaye
Jacques
J
García Fernández
José M
JM
D001386:Azides / Q000737:chemistry; D002234:Carbodiimides / Q000737:chemistry; D002241:Carbohydrates / Q000138:chemical synthesis*; D017879:Isothiocyanates / Q000138:chemical synthesis*; D009943:Organophosphorus Compounds / Q000737:chemistry
D001386:Azides; D002234:Carbodiimides; D002241:Carbohydrates; D017879:Isothiocyanates; D009943:Organophosphorus Compounds; C061896:triphenylphosphine