Concept explainers
Interpretation:
For the four isomeric
Concept introduction:
The absolute configuration is the three dimensional spatial arrangement of substituents at the chiral center.
The R and S configuration at the chiral center is assigned on the basis of Cahn-Ingold-Prelog rules.
The molecule is oriented such that the lowest ranked group points away from the observer.
If the remaining three groups in order of decreasing priority trace a clockwise path, the configuration is R.
If the remaining three groups in order of decreasing priority trace a counter clockwise path, the configuration is S.
In Fischer projections, the molecule is oriented such that the vertical bonds attached to the chiral center are directed away from the observer and the horizontal bonds point towards the observer.
When two groups are exchanged in a Fischer projection, it reverses the configuration of the chiral center.
Enantiomers are the mirror images of each other; they have opposite configuration at the each chirality center.
Diastereomers have at least two chiral centers and they are not mirror images of each other; they must have an opposite configuration for at least one chirality centers.
Want to see the full answer?
Check out a sample textbook solutionChapter 4 Solutions
Organic Chemistry - Standalone book
- III. Consider the compound below. CH, CI- Br но O- H. (Atomic number: H-1, C-6, O-8, CI-17, Br-35) a. How many chiral centers are in the molecule? b. How many stereoisomers are there for the compound? c. Draw the Fischer projection for each of the stereoisomer and determine the absolute configuration (R or S). Label each using I, II, etc. d. Which pairs are enantiomers? Which are diastereomers?arrow_forwardDraw the perspective structure and Fischer projection for the following compounds with 2 asymmetric carbon.1. (2R,3S)-2-bromo-3-iodobutane2. (2S,3R)-2-bromo-3-iodobutane3. (2R,3R)-2-bromo-3-iodobutane4. (2S,3S)-2-bromo-3-iodobutanearrow_forwardOn the molecule below, highlight all R stereocenters in red and all S stereocenters in blue. If it doesn't contain any stereocenters, check the "No Stereocenters" box under the drawing area. H Śarrow_forward
- 1. Assign priorities to each group on the chirality center in the molecule below (show the priority in the box next to the indicated group). Assign the configuration (R or S) of that chirality center (in the box to the right). 07 OH Configuration:arrow_forward4. Draw the compound, 2-pentanol, shown on the PubChem website. Label any stereocenter(s) as to their absolute configuration, e.g. R or S. 5. Is there a plane of symmetry in 2-pentanol, yes or no? 6. Is 2-pentanol chiral or achiral?arrow_forwardTasks Demonstrate the usefulness of Fischer projections by showing how it is easy to determine isomeric relationship between two structures. 1. Convert both isomers in Figure 8 to Fischer projections. 2. Identify the stereoisomeric relationship between the isomers. Briefly explain the process. ОН CI Br „Br "CI HO, isomer A isomer B Figure 8: Isomersarrow_forward
- Use a Fischer projection to describe the stereochemistry of (R)-2-chlorobutane by dragging the functional groups to the appropriate box in the figure. Cl CH₂CH3 Answer Bank CH₂ Harrow_forward1. Below is the Fischer projection of a molecule. Is this the (R) or (S) enantiomer? 2. If you swap the positions of the H and the Cl, does this represent the same enantiomer or the opposite one? 3. Having swapped the positions of the H and CI, if you then swap the Cl and methyl group, what happens to the stereochemistry of the chiral center? CH3 H- CI CH,CH3arrow_forward11. Identify the correct configurations (R or S) of the chirality centers indicated on the Fischer projection shown below.arrow_forward
- Is my answer to this fischer projection conversion correct?arrow_forwardA sulfonium ion (R3S+) is a stereogenic center if three different alkyl groups are bonded to sulfur because sulfur is surrounded by four different groups, including its lone pair. In assigning an R or S) is a stereogenic center if three different alkyl groups are bonded to sulfur because sulfur is surrounded by four different groups, including its lone pair. In assigning an designation to sulfur, the lone pair is always assigned the lowest priority (4). SAM, S -adenosylmethionine, is a biologically active sulfonium ion that we will learn about in Section 7.16. Locate all the stereogenic centers in SAM, and assign an R,S designation to each center.arrow_forward2. The following molecule is one enantiomer of methylenedioxymethamphetamine (MDMA). 2a. Circle all of the stereocenters in MDMA 2b. Assign the absolute stereochemistry (R or S) for each stereocenter .CH3 HN H H *CH3arrow_forward
- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning