The most stable conformation of most aldopyranoses is one in which the largest group, the iCH2OH group,

Question:

The most stable conformation of most aldopyranoses is one in which the largest group, the iCH2OH group, is equatorial. However, d-idopyranose exists primarily in a conformation with an axial --CH2OH group. Write formulas for the two chair conformations of a-d-idopyranose (one with the --CH2OH group axial and one with the --CH2OH group equatorial) and provide an explanation.