The question asks to identify the structure of L-(-) glucose given the structure of D-(+) glucose. This involves understanding stereochemistry and enantiomers in carbohydrate chemistry.

Key Concept: Enantiomers

D-glucose and L-glucose are enantiomers - non-superimposable mirror images of each other. They have identical physical and chemical properties except for their interaction with plane-polarized light (optical activity) and biological systems.

The D/L designation refers to the configuration at the chiral center farthest from the carbonyl group (in glucose, this is carbon 5). In the Fischer projection:

D-sugar: The -OH group on the highest numbered chiral carbon is on the RIGHT side
L-sugar: The -OH group on the highest numbered chiral carbon is on the LEFT side

To convert D-glucose to L-glucose, we simply invert the configuration at all chiral centers while keeping the carbon skeleton identical.

Step-by-Step Identification

Given the D-(+) glucose structure, the L-(-) glucose will be its exact mirror image:

Compare the configuration at each chiral center
Look for the structure where ALL chiral centers are inverted
Verify that the carbon skeleton remains identical (same connectivity)
The correct L-glucose should show the -OH group on carbon 5 on the LEFT side

Related Topics

Stereoisomerism: The study of molecules with the same molecular formula and connectivity but different spatial arrangement of atoms.

Optical Activity: The ability of chiral molecules to rotate plane-polarized light. D-glucose is dextrorotatory (+), while L-glucose is levorotatory (-).

Important Formulae

While no mathematical equations are needed for this identification, remember that:

Specific rotation: $[α] T λ = \frac{α}{l \times c}$

where α is the observed rotation, l is the path length, and c is the concentration.