Reactions at Oxygen Atoms
2.1
125
⊡ Scheme 22
Examples of protection of diequatorial vicinal diols with dispiroketals
⊡ Scheme 23
Acid-catalyzed formation of 1,2-diacetals from 1,2–trans-diols
highly crystalline materials but they have very desirable NMR features that help analysis of
the products since the methyl groups act as useful diagnostic markers. As with CDA, BDA
groups are readily removed at the end of the synthetic sequence.
Pyruvate Acetals Pyruvate ketals are present in many lipopolysaccharides of bacterial origin,
in capsular polysaccharides ( > Fig. 3) [154], and also in glycolipids isolated from fish nerve
fibers [155]. As a result of the unique structural features including the presence of a negative charge on the carboxyl functional group and the chiral center, pyruvate ketals influence
immunological specificity and patterns of immunological cross reactivity and therefore play
an important role in cell–cell recognition processes [156]. Hexopyranosides containing pyru-
2.1
125
⊡ Scheme 22
Examples of protection of diequatorial vicinal diols with dispiroketals
⊡ Scheme 23
Acid-catalyzed formation of 1,2-diacetals from 1,2–trans-diols
highly crystalline materials but they have very desirable NMR features that help analysis of
the products since the methyl groups act as useful diagnostic markers. As with CDA, BDA
groups are readily removed at the end of the synthetic sequence.
Pyruvate Acetals Pyruvate ketals are present in many lipopolysaccharides of bacterial origin,
in capsular polysaccharides ( > Fig. 3) [154], and also in glycolipids isolated from fish nerve
fibers [155]. As a result of the unique structural features including the presence of a negative charge on the carboxyl functional group and the chiral center, pyruvate ketals influence
immunological specificity and patterns of immunological cross reactivity and therefore play
an important role in cell–cell recognition processes [156]. Hexopyranosides containing pyru-