BackThe α- and β-anomers of glucose are shown here. In solution, these two epimers can interconvert through a process called mutarotation.
Given that α-D-glucose has a specific rotation of + 112.2° , why is the specific rotation of β-D-glucose not -112.2°? What molecule would have a specific rotation of -112.2°?
Upon dissolving α-D-glucose or β-D-glucose in water, the specific rotation gradually changes, eventually reaching +52.6° for both solutions. Explain what is happening here.
Questions (a)–(d) all refer to the following reaction, which has been engineered to produce one enantiomer to the exclusion of the other.
(c) Suppose the difference in activation energy is 1.6 kcal/mol. At what temperature would you produce C in 99% ee?
How might you separate enantiomers of 2-phenylpropionic acid?
A chemist prepared a racemic mixture of the enantiomeric sulfonic acids shown here. Suggest two ways that these might be separated.
When 0.200 g of lactose is dissolved in 10.0 ml of water and placed in a sample cell 10.0 cm in length, the observed rotation is +2°. Calculate the specific rotation of lactose.
Chromatography using a chiral stationary phase is able to separate a pair of enantiomers because one of the enantiomers forms a more tightly bound complex with the stationary phase. Assuming that the (S) enantiomer elutes more slowly, rationalize this result on a reaction coordinate diagram.
Figure 6.52 <IMAGE> shows the lipase-catalyzed kinetic resolution of secondary alcohols. Show a reaction coordinate diagram that rationalizes the results obtained.