Ch. 24 - CarbohydratesSee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

We know that aldose aldehydes are susceptible to the same nucleophilic addition reactions that we learned in carbonyl chemistry. Let's now learn a reaction that involves the formation of a cyanohydrin. The neat thing about this reaction is that the cyano group can then be reduced and hydrolyzed to form a new, chain-lengthened aldehyde.

Concept #1

The original Kiliani-Fischer synthesis required two additional steps after cyanohydrin addition, and resulted in poor yields. However, an improved reducing agent, (H2, Pd/BaSO4), was developed to form imines instead of amines.

Concept #2

Ready for a practice problem?

Practice: Predict the product(s) for the following reaction. Provide the mechanism of the imine hydrolysis step if required.