Waiting for answer This question has not been answered yet. You can hire a professional tutor to get the answer.

QUESTION

# How can I draw d -glucose in its chair conformation? Why it is the most common aldohexose in nature?

First convert the Fischer projection to a Haworth projection, then convert the Haworth projection to a chair form.

The Fischer projection of glucose is

Convert to a Haworth Projection

Step 1. Draw a basic Haworth projection with the ring oxygen at the top.

"C-1" is the atom to the right of the oxygen, and "C-5" is the atom to its left.

Step 2. Draw a "CH"_2"OH" on "C-5".

Step 3. Draw an "OH" below the ring on "C-1" for the α form (draw it above the ring for the β form).

Step 4. Draw all the "OH" groups on the right side of the Fischer projection on the bottom of the ring. Those on the left go above the ring.

The "O" on C-5 is part of the ring.

You can omit the hydrogen atoms, so the Haworth projection for α-D-glucopyranose is

Convert Haworth to Chair

Step 1. Draw a cyclohexane chair in which the "O" atom replaces "C-6" and the bulky "CH"_2"OH" is in the equatorial position.

Step 2. Put all the "OH" groups that are "down" in the Haworth projection "down" in the chair. All the other "OH" groups go "up".

The chair form of α-D-glucopyranose is

The structure of β-D-glucopyranose is

Prevalence of Glucose

As you move around the β-glucose ring, you see that all the substituents are equatorial.

This is the most stable arrangement possible.

In α-glucose, only the "OH" at "C-1" is axial.

Every other aldohexose would have more axial substituents and be less stable.

Glucose is the most common hexose because it is the most stable.