Skip to main content
Ch.15 Aldehydes and Ketones
McMurry - Fundamentals of General, Organic, and Biological Chemistry 8th Edition
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoMcMurry 8th EditionCh.15 Aldehydes and KetonesProblema 17
Capitolo 15, Problema 17

For each compound shown next, determine whether it is a hemiacetal, a hemiketal, an acetal, or a ketal.
a.
b.
c.
d.

Guida verificata passo dopo passo
1
Step 1: Understand the definitions of the terms. A hemiacetal contains one -OH group and one -OR group attached to the same carbon atom, which is also bonded to a hydrogen atom. A hemiketal is similar but the central carbon is bonded to two alkyl groups instead of a hydrogen. An acetal contains two -OR groups attached to the same carbon atom, which is also bonded to a hydrogen atom. A ketal is similar to an acetal but the central carbon is bonded to two alkyl groups instead of a hydrogen.
Step 2: Examine the structure of compound (a). Look for the functional groups attached to the central carbon atom. Identify whether the central carbon is bonded to a hydrogen atom or two alkyl groups, and whether it has one or two -OR groups.
Step 3: Repeat the process for compound (b). Carefully analyze the functional groups attached to the central carbon atom and determine whether it fits the definition of a hemiacetal, hemiketal, acetal, or ketal.
Step 4: Analyze compound (c) in the same way. Pay attention to the number and type of groups attached to the central carbon atom, and compare them to the definitions provided in Step 1.
Step 5: Finally, evaluate compound (d). Use the same approach to identify the functional groups and classify the compound as a hemiacetal, hemiketal, acetal, or ketal based on the structural features.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
1m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Hemiacetals and Hemiketals

Hemiacetals and hemiketals are formed when an alcohol reacts with an aldehyde or a ketone, respectively. A hemiacetal contains one -OH group and one -OR group attached to the same carbon, while a hemiketal has two -OR groups. These compounds are typically unstable and can further react to form acetals or ketals.
Video consigliato:
Percorso guidato
2:10
Cyclic Hemiacetals Concept 1

Acetals and Ketals

Acetals and ketals are derived from hemiacetals and hemiketals through a reaction with an alcohol, resulting in the replacement of the -OH group with another -OR group. Acetals have two -OR groups attached to the carbon that was originally part of the aldehyde, while ketals have two -OR groups attached to the carbon from the ketone. These compounds are generally more stable than their hemi counterparts.
Video consigliato:
Percorso guidato
2:17
Formation of Hemiacetals and Acetals Concept 2

Structural Identification

To determine whether a compound is a hemiacetal, hemiketal, acetal, or ketal, one must analyze its structure. This involves identifying the functional groups present, such as -OH and -OR, and the carbon's connectivity to determine if it originated from an aldehyde or ketone. Understanding the structural features is crucial for accurate classification.
Video consigliato:
Percorso guidato
1:01
Structural Formula Concept 2
Pratica correlata
Domanda del libro di testo

The carbonyl group can be reduced by addition of a hydride ion (H–) and (H+) a proton. Removal of H– and H+ from an alcohol results in a carbonyl group.

a. To which atom of the carbonyl is the hydride ion added and why?

798
views
Domanda del libro di testo

Draw the structures of the hemiacetals or hemiketals formed in these reactions: 

b.

792
views
Domanda del libro di testo

The carbonyl group can be reduced by addition of a hydride ion (H–) and (H+) a proton. Removal of H– and H+ from an alcohol results in a carbonyl group.

b. In the reaction, indicate which direction represents reduction and which represents oxidation.

895
views
Domanda del libro di testo

Determine whether the following compounds are acetals or ketals. Draw the structure of the aldehyde or ketone it came from.

c.

857
views
Domanda del libro di testo

A fundamental difference between aldehydes and ketones is that one can be oxidized to carboxylic acids but the other cannot. Which is which? Give an example of a test to differentiate aldehydes from ketones.

794
views