Section 22-3

The carbanions are stable enough to exist in solution.

Many of the nucleophilic reaction types have been covered previously. Enolates are strong bases and usually need an acidic workup to supply H+.

Dehydration often leads to the formation of aldol condensations.

Chapter 22 has reactions shown in red. Reactions are shown in blue.

A ring is formed by Claisen condensation.

The carbon atom is deprotonated next to a carbonyl group.

Such a hydrogen may be lost and regained through tautomerism.

The acylation of malonic ester is followed by the hydrolysis and decarbox ylation.

Robinson is followed by an aldol condensation with dehydration.

The acylation of a ketone or aldehyde involves the use of an enamine derivative.

The alkylated or acylated ketone or aldehyde can be regenerated.

An isomerism involves the movement of a double bond and a protons.

tautomerism is related to the isomers.

condensations take on a wide variety of forms in this chapter. To gain confidence in working out new variations of the standard mechanisms, you need to work enough problems. Make sure you can propose condensations that form new rings.

Each skill is followed by problem numbers.

There are mechanisms for acid-catalyzed and base-catalyzed keto-enol tautomerisms.

There are mechanisms for these reactions.

There are mechanisms for acid-catalyzed and base-promoted alpha-halogenation of ketones.

Predict the reactions of aldol before and after dehydration. Acid-catalyzed and base-catalyzed reactions have mechanisms.

Predict the Claisen condensations and propose mechanisms.

These Problems are 22-69, 72, 73, 74, 79, reactions.

Predict the products of conjugate additions and show how to use them.

The compounds should be ranked in order of increasing acidity.

List the compounds that would be more than 99% deprotonated by a solution of sodium ethoxide.

There is a mixture of 8% keto and 92% enol forms. Explain the stability of the stable enol tautomer.

In order to increase acid strength, rank these compounds.

In order to increase enol content, rank these compounds. Draw the most stable enol.

Show how you would use Robinson to make these compounds.

You can show how you would make each compound with aldol, Claisen, or another type of condensation.

How would you accomplish the following conversions? You can use any necessary reagents.

The following compounds would be made using the malonic ester synthesis.

The acetoacetic ester synthesis would be used to make the following compounds.

The following compounds can be made using aldol condensations.

In the case of the aldol condensation, an active methylene compound reacts with an aldehyde or ketone, in the presence of a secondary amine as a basic catalyst, to produce a new C.

The following enamine alkylation and acylation reactions have expected products. After the iminium salts are hydrolysis, give the final products.

The following multistep conversions would be accomplished by showing how you would accomplish them. You can use any additional reagents.

Many of the condensations we studied are not permanent. There are mechanisms to account for the reactions.

The chemistry lab students added an excess of ethylmagnesium bromide to methyl furoate, expecting the Grignard reagent to add twice and form the tertiary alcohol. The product was a mixture of two compounds. The expected product had two ethyl groups, but the unexpected product had three. There is a mechanism to explain the formation of the unexpected product.

The mechanism for the reaction should be proposed.

The splitting of fructose-1,6-diphosphate to give glyceraldehyde- 3-phosphate is a reaction involved in the metabolism of sugars. The base-catalyzed reaction can be proposed.

Scientists studying the structure of collagen found cross-links with unsaturated aldehydes.

Draw the structures of glucose, its anomers, and its epimers, both as Fischer projections and chair conformations.

Draw their structures from their names.

Predict the reactions of carbohydrates with acidic and basic solutions. Predict the reactions that convert their carbonyl groups to acetals.

Biochemists have found that cells in organisms recognize other cells by the pattern of sugars on their surfaces. White blood cells can identify foreign cells as pathogens if the polysaccharide sequence on the foreign cell surface does not match the usual sequence. Red blood cells have patterns of sugar that identify them as different types of blood. Blood cells with d-galactose at the end of the sequence. Both types of blood cells have the same sequence.

Carbohydrates are the most abundant organic compounds. Plants and animals use carbohydrates to store energy and deliver it to their cells.

Most living organisms use water and carbon dioxide as oxidizers. The plants can get the units from the starch. The storage unit for solar energy is called the starch.

Carbohydrates are in one form or another in almost every aspect of human life.

Like other animals, we use the energy in our food to produce and store energy in our cells. In cells, they form links to lipids to make glycoproteins, which serve important functions in the immune system, hormones, and cell membranes. Cotton and linen are used to make clothing. We use wood to build houses and as a fuel to heat them. The page is made from fibers.

Carbohydrate chemistry is one of the more interesting areas of chemistry.

Many chemists are employed by companies that make food, building materials, and consumer products. All biologists need to understand the roles of Carbohydrates in the plant and animal kingdoms. The structures and reactions of carbohydrates may seem complicated at first glance. We can study the simplest organic compounds as easily as we study the more complex structures and reactions.

Sugars have a sweet taste. C(H2O) is the empirical formula of most simple sugars.

These compounds are called "hydrates of carbon" or "carbohydrates" because of their formulas.

Both sugars are polyhydroxyaldehydes and are projected toward the viewer and ketone.

H OH is the abbreviation for H C* OH.

The IUPAC name is always at the top of the projection. The second carbon from the top is usually the Fischer projection carbonyl group.

There are mirror images of arabinose and erythrose.