Question

Why is D-glucose the most common aldohexose in nature?

Answer 1

D-Glucose is the most common aldohexose in nature because in its cyclic form it is the most stable of all the aldohexoses.

We normally write the structure of D-glucose as

But we must remember that D-glucose exists as a cyclic hemiacetal.

Let's re-draw this as a cyclohexane chair.

Now we see why glucose is so stable.

Every substituent is in an equatorial location!

Every other aldohexose must have at least one substituent in a less stable axial location.