Anhydrosugars
2.4
283
⊡ Scheme 15
of the oxirane ring [34] afforded the D-ribo-C-glycoside 43, while the cis-opening with aluminum compounds provided the D-arabino-C-glycoside 41. Both were further converted into
the same 2-deoxy derivative 42 ( > Scheme 15) [35].
2.4 1,3- and 1,4-Anhydrosugars
Such derivatives are obtained by reaction of partially protected glycosyl chlorides with a strong
base (NaH, t BuOK) in THF. The alternative version consists of treatment of the 4-O- or 5-O⊡ Figure 8
Examples of the 1,3- and 1,4-anhydropyranoses
2.4
283
⊡ Scheme 15
of the oxirane ring [34] afforded the D-ribo-C-glycoside 43, while the cis-opening with aluminum compounds provided the D-arabino-C-glycoside 41. Both were further converted into
the same 2-deoxy derivative 42 ( > Scheme 15) [35].
2.4 1,3- and 1,4-Anhydrosugars
Such derivatives are obtained by reaction of partially protected glycosyl chlorides with a strong
base (NaH, t BuOK) in THF. The alternative version consists of treatment of the 4-O- or 5-O⊡ Figure 8
Examples of the 1,3- and 1,4-anhydropyranoses