Glycal Derivatives
3.6
711
⊡ Scheme 14
theses of glycals, deprotonation is facilitated by placing a strong electron-withdrawing group
at the anomeric position. For example, C-glycosyl derivative 46 undergoing acetic acid elimination upon treatment with pyridine at room temperature easily affords 47 in a 75% yield
( > Scheme 15) [149].
Easily available anomeric sulfones, which have already been mentioned as glycal precursors,
readily undergo base-induced eliminations resulting in formation of 1,2-unsaturated pyranose derivatives in which the sulfonyl group has been retained [150,151]. Such compounds
have considerable synthetic potential, particularly for C–C bond formation. For example,
compound 49 can be lithiated with LDA/THF at 80 °C to afford C-2 branched glycals 50
( > Scheme 16) [152].
⊡ Scheme 15
⊡ Scheme 16
3.6
711
⊡ Scheme 14
theses of glycals, deprotonation is facilitated by placing a strong electron-withdrawing group
at the anomeric position. For example, C-glycosyl derivative 46 undergoing acetic acid elimination upon treatment with pyridine at room temperature easily affords 47 in a 75% yield
( > Scheme 15) [149].
Easily available anomeric sulfones, which have already been mentioned as glycal precursors,
readily undergo base-induced eliminations resulting in formation of 1,2-unsaturated pyranose derivatives in which the sulfonyl group has been retained [150,151]. Such compounds
have considerable synthetic potential, particularly for C–C bond formation. For example,
compound 49 can be lithiated with LDA/THF at 80 °C to afford C-2 branched glycals 50
( > Scheme 16) [152].
⊡ Scheme 15
⊡ Scheme 16