Question

Draw the Fischer projection formula of D-glyceraldehyde. Explain the positions of different groups in the molecule. How are the higher sugars assigned configuration on the basis of Fischer projection formula?

Answer 1

fissure projection of glyceraldehyde explains about the arrangement of hydroxyl and hydrogen moiety in the compound as shown in figure.

Hydroxyl group is present in right side of the chain explaining the D name as dextro.

For higher saccharides with long carbon chain, the arrangement through fissure projection is shown as in the figure. The carbon present in the middle of the chain is shown by compressing them by CH2 and indicating the number of carbon out of the bracket.