28. Carbohydrates

Convert the following monosaccharide into its Fischer representation. Is it a D or L-isomer?

Convert the following monosaccharide into a bondline representation.

The relative configurations of the stereoisomers of tartaric acid were established by the following syntheses:

(1) D-(+)-glyceraldehyde $\stackrel{HCN}{\to }$ diastereomers A and B (separated)

(2) Hydrolysis of A and B using aqueous Ba(OH)₂ gave C and D, respectively.

(3) HNO₃ oxidation of C and D gave (-)-tartaric acid and meso-tartaric acid, respectively.

(a) You know the absolute configuration of D-(+)-glyceraldehyde. Use Fischer projections to show the absolute configurations of products A, B, C, and D.

(b) Show the absolute configurations of the three stereoisomers of tartaric acid: (+)-tartaric acid, (-)-tartaric acid, and meso-tartaric acid.

Draw Fischer projections of L-glucose and L-fructose.

Convert each line-angle drawing, using appropriate bond rotations, into a correct Fischer projection.

(a)

Convert each line-angle drawing, using appropriate bond rotations, into a correct Fischer projection.

(b)

Convert each line-angle drawing, using appropriate bond rotations, into a correct Fischer projection.

(c)