What is the configuration of each of the asymmetric centers in the Fischer projection of
d. D-xylose?

Verified step by step guidance

Step 1: Understand the Fischer projection of D-xylose. D-xylose is a five-carbon aldose sugar with the aldehyde group (-CHO) at the top and the hydroxymethyl group (-CH2OH) at the bottom. The asymmetric centers are the carbons bonded to four different groups.

Step 2: Identify the asymmetric centers in D-xylose. These are the carbons in the middle of the Fischer projection that are bonded to a hydrogen atom, a hydroxyl group (-OH), and two other groups.

Step 3: Assign priorities to the substituents around each asymmetric center based on the Cahn-Ingold-Prelog (CIP) rules. The substituent with the highest atomic number gets the highest priority.

Step 4: Determine the configuration (R or S) of each asymmetric center. To do this, visualize the molecule in 3D, ensuring the lowest priority group (usually hydrogen) is pointing away from you. Trace the path of the remaining groups in order of priority (1 → 2 → 3). If the path is clockwise, the configuration is R; if counterclockwise, it is S.

Step 5: Repeat the process for each asymmetric center in D-xylose. Carefully analyze the Fischer projection to ensure the correct assignment of configurations for all chiral centers.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Fischer Projections

Fischer projections are a two-dimensional representation of three-dimensional organic molecules, particularly carbohydrates. In these projections, vertical lines represent bonds that extend away from the viewer, while horizontal lines indicate bonds that come towards the viewer. This format is particularly useful for visualizing the stereochemistry of molecules, especially those with multiple chiral centers.

Chirality and Asymmetric Centers

Chirality refers to the property of a molecule that makes it non-superimposable on its mirror image, often due to the presence of asymmetric centers (chiral centers). Each asymmetric center in a molecule can exist in two configurations, typically designated as 'R' (rectus) or 'S' (sinister), based on the Cahn-Ingold-Prelog priority rules. Understanding chirality is crucial for determining the optical activity and biological interactions of molecules.

D and L Notation

The D and L notation is used to classify sugars based on the configuration of their asymmetric carbon furthest from the aldehyde or ketone group. In D-sugars, the hydroxyl group (-OH) on this carbon is on the right in the Fischer projection, while in L-sugars, it is on the left. This notation is essential for distinguishing between different stereoisomers of sugars, which can have vastly different biological functions.

What is the configuration of each of the asymmetric centers in the Fischer projection of d. D-xylose?