Concept explainers
Interpretation:
The configuration of (+)-2-methyl-1-butanol has to be determined from the given structure of (-)-2-methyl-1-butanol.
Concept introduction:
The pair of Enantiomers has different configurations.
Enantiomers are named by following Cahn-Ingold-Prelog system, in which R or S letter is used to differentiate between enantiomers.
According to Cahn-Ingold-Prelog system,
The group attached to asymmetric center should be ranked based on the
Check the direction of arrow drawn in the direction of decreasing priority. If the arrow points clockwise direction, then the compound has R configuration. If the arrow points counterclockwise direction, then the compound has S configuration. If the group with lowest priority is not bonded by a hatched wedge, then interchange this group (lowest priority) by group bonded to hatched wedge and draw the arrow in priority order but the configuration is assigned as just reverse.
Pair of enantiomers has different optical activity, which means if one will show levorotatory then the other will show dextrorotatory.
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Chapter 4 Solutions
Organic Chemistry (8th Edition)
- Identify any chiral centers within the 2 molecules and identify whether each molecule is chiral or archial. If it is chiral, explain whether you expect a single enantiomer or a mixture of enantiomers to be formed.arrow_forwardDraw a three-dimensional structure for each compound, and star all asymmetric carbon atoms. Draw the mirror image for each structure, and state whether you have drawn a pair of enantiomers or just the same molecule twice. Build molecular models of any of these examples that seem difficult to you. (a) ОН (b) (c) NH, ОН СH—CH—СООН | pentan-2-ol pentan-3-ol alanine (d) 1-bromo-2-methylbutane (e) chlorocyclohexane (f) cis-1,2-dichlorocyclobutane (h) (i) H CH; "H H. H CH, Harrow_forwardDraw and name all the stereoisomers of 2-bromo-3-iodopentane. Indicate which stereoisomers are enantiomers and which are diastereomers.arrow_forward
- 12. Natural (2)-menthol, the essential oil primarily responsible for the flavor and aroma of peppermint, is the IR,25,5R-stereoisomer. (a) Identify (2)-menthol from the structures you drew for Problem 50, part (b). (b) Another of the naturally occurring diastereomers of menthol is (1)-isomenthol, the 1S 2R5R- stereoisomer. Identify (1)-isomenthol among your structures. (c) A third is (1)-neomenthol, the 15.25,SR-compound. Find (1)-neomenthol among your structures. (d) Based on your understanding of the conformations of substituted cyclohexanes (Section 4-4), what is the stability order (from most stable to least) for the three diastereomers, menthol, isomenthol, and neomenthol?arrow_forwardThe reaction of (R)-1-iodo-2-methylbutane with hydroxide ion forms an alcohol without breaking any bonds to the asymmetric center. The alcohol rotates the plane of polarization of plane-polarized light counterclockwise. What is the configuration of (+)-2-methyl-1-butanol?arrow_forwardDetermine the R/S orientation of the indicated chiral center(s) in the following molecules. If there is only one chiral center in the molecule, choose (none). OH H3C- -CH3 Molecule #1 (sobrerol): Center a: Center b: Molecule #2 (pulegone ): Center a: V Center b: HO H3C a CH3 CH3 CH3arrow_forward
- What are the configurations of the chiral carbon atoms in this compound? Carbon atom number 1 is the carbon containing the aldehyde. H H HO- CHO OH -OH -H CH₂OH (2R 3R,4S) O (25,35,45) Ⓒ (25,35,4R) O (2R,35,45) O (2S,3R.4R) O (2R 3R,4R) Ⓒ(2S,3R.4S) O (2R,3S,4R)arrow_forward8. Two structures of Lipitor (a drug used to lower cholesterol) are shown below. (a) Determine the absolute configuration of each indicated stereocenter. Fill in the correct circle. (b) Determine if the two structures are the same compound or stereoisomers. Fill in the correct circle. (a) НО. Carbon a HO O OH Carbon a: OR OS Carbon b H N Carbon b: R OS of H Carbon c: OR OS OH OH Carbon c F Carbon d: R OS OH Carbon d (b) The two structures are: O the same compound O stereoisomersarrow_forward(9) How many chiral centers are present in a molecule of 1,3-dimethylcyclohexane? (C) 2 (D) 3 1 (A) O (10) What is the percent composition of a mixture of (S)-(+)-2-butanol, [a] = +13.52°, and (R)-(-)-2-butanol, [a] = -13.52°, with a specific rotation [a]D = -6.76° (A) 75%R 25%S (B) 25%R 75%S (C) 50%R 50%S 67%R 33%Sarrow_forward
- VIII. Assign R, S configurations to each chirality center in the molecule below. Br CH3 X OH CH3 I I (arrow_forward7 For the following compound with two chiral centers assign 'R' and 'S' configurations. Draw enantiomers and diastereomers for the following compound? How many enantiomers and diastereomers are possible. Assign (R) and (S) configurations for all the structures. What are diastereomers? COOH H CI € Br -H CH3arrow_forward(A)Menthol, used to flavor various foods and tobacco, is the most stable stereoisomer of 2-isopropyl-5-methylcyclohexanol. Draw its most stable conformation. Is the hydroxyl group cis or trans to the isopropyl group? To the methyl group? (b) Neomenthol is a stereoisomer of menthol. That is, it has the same constitution but differs in the arrangement of its atoms in space. Neomenthol is the second most stable stereoisomer of 2-isopropyl-5methylcyclohexanol; it is less stable than menthol but more stable than any other stereoisomer. Write the structure of neomenthol in its most stable conformation.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning