110b Exam 7 Review Sheet- Spring Semester 2014
Review Session: 7:00 PM, May 7, SN 111
Exam 7: 9:00 AM, May 13, SN 111
Chapter 22:
1.
Classification of carbohydrates (22.2A, 22.2B), D and L designation- historical aspects and use of
glyceraldehyde as a reference compound, Bijvoet’s contribution to this use of stereochemical
descriptors. Review the R/S system and be able to correlate this system with the D/L system for
glyceraldehyde and the optically active tartaric acids. 9E: 979-984, 10E: 1001-1005.
2.
Structural formulas for monosaccharides: be able to translate a Fischer projection into a pyranose,
furanose, or lactone, depending upon the C.1 oxidation state. Be able to do this translation in the
opposite direction as well. Def of  and  pyranose/furanose and pyranoside/furanoside. Use Dglucose as your practice molecule in these transformations-- every organic chemist should know
the structure of this sugar. 11E: 984-987, 10E: 1005-1009.
3.
Mutarotation (def.) for hemiacetals and hemiketals--mechanism of this process. 11E: 987-988,
10E: 1009-1010.
4.
Glycoside formation- know the mechanism of this process. Definition of aglycone. 11E: 988990, 10E: 1010-1013.
5.
Origin of the stereoelectronic effects (the anomeric effect) used to explain axial preference of
glycosides, and the enhanced axial preference seen in six-membered hemiacetals (e.g., glucose).
Relevance of substituted cyclohexanes (OH, OMe) in these discussions. Class handout.
6.
Reactions of monosaccharides: methylation, benzylation, esterification, cyclic acetals and ketals
(rules for formation-- 1,3 diols can also undergo this reaction); nature of Tollen’s Benedict’s or
Fehling’s solutions: def. of reducing or nonreducing sugars; Bromine water oxidation of aldosesoutcome of reaction and potential lactone formation; nitric acid oxidation of aldoses--outcome of
reaction and potential lactone formation; periodate oxidations- mechanism and outcome (glycerol,
glyceraldehyde, and dihydroxyacetone) of reaction and utility in structure elucidation; reductions
of aldoses and ketoses with NaBH4 or H2/Pt. 11E: 990-1003, 10E: 1013-1025.
7.
Fischer’s proof of the relative configuration of glucose: no need to memorize the structures
involved, but be familiar with the reactions (mechanisms not required) and general strategy used
to eliminate the possible structures (know how to predict the maximum number of structures for a
given sugar (e.g., 4 carbon, 5 carbon, 6 carbon, 7 carbon). Could you, for example, use the tools
that Fischer had and propose the relative configuration of an aldopentose, given ample exptl. data?
11E: 1003-1005, 10E: 1027-1029.
8.
The structure of sucrose-- every organic chemist should know it. Review the evidence for its
structure. 11E: 1005-1006, 10E: 1029-1030.
9.
The structure of maltose and cellobiose-- these are easy to remember because they are both
glucose- based and differ only at the glycoside linkage. Review the structural evidence for
maltose and check the method used to determine the nature ( ) of the glycosidic linkage in
each. 11E: 1006-1008, 10E: 1030-1032.
10.
Polymerize maltose to starch (amylose) and do the same for cellobiose. Examine the resulting
structures (Fig. 22.14, 22.17) and recognize the dramatic differences in secondary structure-- a
direct consequence of different primary structure. Be able to explain the origins of the exoanomeric ffect and how this stereoelectronic effect contributes to the observed three-dimensional
structure of cellulose and amylose. Explore the structural similarities of chitin and cellulose. 11E:
1009-1015, 10E: 1033-1039.
Suggested Problems for Exam 7. Chapter 22, 20-40 even (10E or 11E).