Question

Question: Convert each aldohexose to the indicated anomer using a Haworth projection

Short answer

Answer

Step-by-step solution

Haworth projection

A Haworth projection is the representation of cyclic hemiacetals of glucose and other sugars that are flat, six-membered rings.

The cyclic forms of glucose contain five stereogenic centers. Here, the four stereogenic centers are at the starting hydroxy aldehyde and one is at the new anomeric carbon.

Conversion of aldohexose into Haworth projection

• Place the O atom in the upper right corner of a hexagon and add the group on the first carbon counterclockwise from the O atom.
• Place the anomeric carbon on the first carbon clockwise from the O atom.
• Add the substituents at the three remaining stereogenic centers, clockwise around the ring.

Explanation

a. The Haworth projection of the given aldohexose is shown as:

The OH at the right in the Fischer projection is placed below in the Haworth projection.

Conversion into Haworth projection for a.

b. The Haworth projection of the given aldohexose is shown as:

Conversion into Haworth projection for b.

c. The Haworth projection of the given aldohexose is shown as:

Conversion into Haworth projection for c.