Q.4-26 - Organic Chemistry (Mcmurry)

Question

Glucose exists in two forms having a 36:64 ratio at equilibrium. Draw a Skeletal structure of each, describe the difference between them, and tell which of the two you think is more stable

 

Step-by-Step Solution

Answer

Beta-Glucose is more stable.

Skeletal structure

Skeletal structure means the graphical representation of the arrangement of atoms and bonds in a molecule.

Steric strain

Steric strain is an increase in the potential energy of a molecule because of repulsion between nonbonded atoms that approach each other closely.

Axial and equatorial positions:

The bonds found perpendicular to the plane of the ring are called axial bonds, while horizontal bonds present in the plane of the ring are called equatorial bonds.

Skeletal structure of glucose:

$\alpha -Glu\cos eand\beta \text{ - Glucose }$

Stability of structures of glucose:

In the beta-Glucose, all the large groups are pointing along the less-hindered equatorial position while in the alpha-Glucose, one of the groups points along the more-hindered axial position hence providing steric strain making it less stable than beta-Glucose.