Skip to main content
Ch.5 - Stereochemistry
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoWade 9th EditionCh.5 - StereochemistryProblema 23
Capitolo 5, Problema 23

Which configuration (R or S) does the bottom asymmetric carbon have for the D series of sugars? Which configuration for the L series?

Guida verificata passo dopo passo
1
Identify the bottom asymmetric carbon in the Fischer projection of the sugar.
Assign priorities to the four substituents attached to the bottom asymmetric carbon based on the Cahn-Ingold-Prelog priority rules.
Orient the molecule so that the lowest priority group is pointing away from you.
Determine the order of the remaining three groups: if the sequence is clockwise, the configuration is R; if counterclockwise, it is S.
For D sugars, the bottom asymmetric carbon typically has the R configuration, while for L sugars, it typically has the S configuration.

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:
5m

Concetti chiave

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

Chirality and Asymmetric Carbons

Chirality refers to the property of a molecule that makes it non-superimposable on its mirror image, often due to the presence of an asymmetric carbon atom. An asymmetric carbon is a carbon atom bonded to four different groups, leading to two possible configurations, known as enantiomers. Understanding chirality is crucial for determining the R or S configuration of sugars.
Video consigliato:
05:41
Understanding Other Chiral Atoms

Cahn-Ingold-Prelog Priority Rules

The Cahn-Ingold-Prelog (CIP) priority rules are a set of guidelines used to assign priorities to the substituents attached to an asymmetric carbon. According to these rules, the substituents are ranked based on atomic number, with higher atomic numbers receiving higher priority. This ranking is essential for determining whether the configuration is R (rectus, right) or S (sinister, left) when viewing the molecule from a specific orientation.
Video consigliato:
01:48
Why stereoisomers need their own naming system.

D and L Configuration in Sugars

The D and L notation in sugars refers to the configuration of the asymmetric carbon farthest from the aldehyde or ketone group. In D sugars, this carbon has the same configuration as D-glyceraldehyde, while in L sugars, it has the opposite configuration. This distinction is important for understanding the stereochemistry of carbohydrates and their biological roles.
Video consigliato:
06:47
Monosaccharides - D and L Isomerism
Pratica correlata
Domanda del libro di testo

Which of the following compounds are chiral? Draw each compound in its most symmetric conformation, star (*) any asymmetric carbon atoms, and draw any mirror planes. Label any meso compounds. You may use Fischer projections if you prefer.

(e) (R,R)-2,3-dibromobutane

(f)

947
views
Domanda del libro di testo

Which of the following compounds are chiral? Draw each compound in its most symmetric conformation, star (*) any asymmetric carbon atoms, and draw any mirror planes. Label any meso compounds. You may use Fischer projections if you prefer.

(c) (2R,3S)-2-bromo-3-chlorobutane

(d) (2R,3S)-2,3-dibromobutane

1907
views
Domanda del libro di testo

Which of the following pairs of compounds could be separated by recrystallization or distillation?

a. meso-tartaric acid and (±)-tartaric acid (HOOC—CHOH—CHOH—COOH)

1748
views
Domanda del libro di testo

Which of the following pairs of compounds could be separated by recrystallization or distillation?

(b)

1105
views
1
rank
Domanda del libro di testo
Draw the mirror images of glucose and fructose. Are glucose and fructose chiral? Do you expect them to be optically active?
1393
views
Domanda del libro di testo
(a) Give the products expected when (+)@glyceraldehyde reacts with HCN. (b) What is the relationship between the products? How might they be separated? (c) Are the products optically active? Explain.
1458
views