NICKEL(II)-CATALYZED TRANSFORMATIONS OF 5-AZIDO-5-DEOXY-D-GLUCOFURANOSE AND OF 5-AZIDO-5-DEOXY-L-IDOFURANOSE

Nickel(II) catalysed isomerisation reactions of C-5 modified derivativ es of D-glucose as well as L-idose were investigated. 5-Azido-5-deoxy- D-glucofuranose was successfully isomerised into the corresponding D-m anno epimer in good yields. Contrasting this result, in the case of th e 5-modified L-idofuranose probed, no evidence for successful epimeris ation at C-2 could be found. However, this sugar was quantitatively re arranged into the corresponding L-sorbopyranose. Upon extended reactio n periods, the latter underwent degradation to give the coresponding 4 -modified methyl L-xylonate.