Concept explainers
(a)
Interpretation:
The carbon atom must be identified which is migrating and the mechanism for carbocation rearrangement must be drawn.
Concept Introduction:
For carbocation rearrangements, there should be some driving force. One moderately stable carbocation can rearrange to a more stable carbocation or release angle strain.
(b)
Interpretation:
The diastereomeric carbocation which is not formed must be drawn.
Concept Introduction:
When out of the two diastereomers, only one is formed the reaction is called diastereoselective.
(c)
Interpretation:
One driving force must be suggested for the rearrangement of one tertiary carbocation to another tertiary carbocation.
Concept Introduction:
For carbocation rearrangements, there should be some driving force. One moderately stable carbocation can rearrange to a more stable carbocation or release angle strain.
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Chapter 6 Solutions
ORGANIC CHEMISTRY LL PRINT UPGRADE
- 7. Show how you would synthesize each compound using methylenecyclohexane as your starting material. If a chiral product is shown, assume that it is part of a racemic mixture. methylenecyclohexane Br `OH HO а. b. с. d. OCH3 ОН `CI ОН е. f. g. h.arrow_forwardDuring the further development of other prostaglandin-like molecules, it is necessary to replace the cyclopentane ring with the cyclohexene as shown in the reaction scheme below. (Deuterium (D) is a heavier isotope of hydrogen) a) Draw the most stable conformation of the starting material 8 and explain why this is the most stable conformation. b) Draw the reaction mechanism for how 9 is formed from 8 and explain why 10 and 11 are not formed if one assumes the E2 mechanism.arrow_forwarda. Draw clear structures of all the possible distinct 2,3-dibromobutane isomers that can be formed. b. identifying the absolute stereochemistry of each stereocenters. c. Indicate the relationships between each of the structures you have drawn (enantiomers, diastereomers, etc.). d. Choose the (2R,3R)-dibromobutane and draw the most stable and the least stable Newman projection looking at C2-C3 sigma bond.arrow_forward
- Draw the structure resulting from a reaction of: 1. diborane (B₂H6), followed by 2. alkaline hydrogen peroxide (NaOH / H₂O2) with the following alkene. . Use the wedge/hash bond tools to indicate stereochemistry where it exists. . If a group is achiral, do not use wedged or hashed bonds on it. • If the reaction produces a racemic mixture, just draw one stereoisomer.arrow_forward16. Explain why when an alkene undergoes addition with HBr and two stereocenters are produced, four total stereoisomers are generated.arrow_forwardWhich rearrangement would the two example of carbocation below most likely undergo? a. Methyl shiftb. Hydride shiftc. Paradigm shiftd. Equilibrium shiftarrow_forward
- Nonconjugated B,y-unsaturated ketones are in base-catalyzed equilibrium with their conjugated a,ß-unsaturated isomers. The mechanism of interconversion involves the formation of a resonance-stabilized intermediate with three resonance contributors. Draw the structures of these three resonance contributors. OH • You do not have to consider stereochemistry. • Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner. Separate resonance structures using the symbol from the drop-down menu. + *** Sn [Farrow_forwardDraw one of the two enantiomers of the major product from this reaction. Use wedge and dash bonds to indicate stereochemistry where appropriate. Ignore inorganic byproducts. Plea 1. BH3-THF 2. H2O2, NaOH Select to Drawarrow_forwardConsider the reaction of (E)-3-methylhex-3-ene with HBr. Part: 0/3 Part 1 of 3 Draw the structures for (E)-3-methylhex-3-ene and the two major organic products for its reaction with HBr. Be sure to show all stereoisomers using. wedge and dash stereochemistry at any chirality center. 0 0 Click and drag to start drawing a structure. :0 + HBr Click and drag to start drawing a structure.arrow_forward
- 10. Which of these describe a set of enantiomers? a. (2R,3R)-2-bromo-3-chloropentane and (2S,3S)-3-bromo-2-chloropentane b. (2R,3R)-2-bromo-3-chlorpentane and (2R,3S)-2-bromo-3-chloropentane c. (2S,3S)-2-bromo-3-chloropentane and (2S,3R)-2-bromo-3-chloropentane d. (2S,3S)-2-bromo-3-chloropentane and (2R,3R)-2-bromo-3-chloropentane e. None of these.arrow_forwardAcyl transfer (nucleophilic substitution at carbonyl) reactions proceed in two stages via a "tetrahedral intermediate." Draw the tetrahedral intermediate as it is first formed in the following reaction. H3C. ... NH2 HCI/H₂O reflux • You do not have to consider stereochemistry. • Include all valence lone pairs in your answer. • Do not include counter-ions, e.g., Na+, I, in your answer. • In cases where there is more than one answer, just draw one. + 4 n [ ?arrow_forward2. Deuterated benzene, a specialized solvent used for NMR spectroscopy, can be synthesized from benzene in an excess of deuterated bromic acid. Draw the mechanism, until it repeats, for the transformation shown below. (Hint: carbocation intermediate is stabilized by the pi system) benzene xs D-Br D D Darrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage LearningOrganic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning
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