Hemiacetals commonly exist in nature as aldoses such as glucose, and hemiketals commonly exist in nature as ketoses such as fructose. The favorability of the formation of a strain-free six-membered ring and the electrophilicity of an aldehyde combine to strongly favor the acetal form.
Hemiacetals commonly exist in nature as aldoses such as glucose, and hemike.tals common,ly exist in nature as ketoses such as fructose. The favorability of the formation of a strain-free six-membered ring and the electrophilicity of an aldehyde combine to strongly favor the acetal form.