
Concept explainers
(a)
Interpretation:
How the given transform would appear in a synthesis is to be shown.
Concept introduction:
A synthetic trap is a synthesis which prevents the reaction from occurring in the forward direction as planned. This occurs mainly because the reactant molecule contains multiple
The alkylation at alpha carbon atoms in
(b)
Interpretation:
How the given transform would appear in a synthesis is to be shown.
Concept introduction:
A synthetic trap is a synthesis which prevents the reaction from occurring in the forward direction as planned. This occurs mainly because the reactant molecule contains multiple functional groups which interfere in the desired mechanism. However, even when there is only one functional group, a synthetic trap can still arise if a reaction takes place at two or more sites within that functional group. In such cases, regiochemistry is an issue. Regiochemistry is the specific region in the given molecule at which the reaction takes place selectively. We can choose a synthesis according to the regioselectivities of the functional group transformation reactions.
The alkylation at the alpha carbon atoms in ketones is regioselective, and we can control the regioselectivity using appropriate reagents, and the sequence in which the reagents are used. The choice of base dictates which alpha carbon undergoes a reaction. A very strong base such as LDA leads to alkylation at the less substituted alpha carbon atom. whereas a moderately strong base such as tert-butoxide anion leads to alkylation at the more substituted alpha carbon atom. The alkylation occurs using an alkyl halide as an alkylating group.

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Chapter 13 Solutions
Organic Chemistry: Principles and Mechanisms (Second Edition)
- 3. Refer to the data below to answer the following questions: Isoelectric point Amino Acid Arginine 10.76 Glutamic Acid 3.22 Tryptophan 5.89 A. Define isoelectric point. B. The most basic amino acid is C. The most acidic amino acid is sidizo zoarrow_forward3. A gas mixture contains 50 mol% H2 and 50 mol% He. 1.00-L samples of this gas mixture are mixed with variable volumes of O2 (at 0 °C and 1 atm). A spark is introduced to allow the mixture to undergo complete combustion. The final volume is measured at 0 °C and 1 atm. Which graph best depicts the final volume as a function of the volume of added O2? (A) 2.00 1.75 Final Volume, L 1.50 1.25 1.00 0.75 0.50 0.25 0.00 0.00 0.25 0.50 2.00 (B) 1.75 1.50 Final Volume, L 1.25 1.00 0.75 0.50- 0.25 0.00 0.75 1.00 0.00 0.25 Volume O₂ added, L 2 0.50 0.75 1.00 Volume O₂ added, L 2 2.00 2.00 (C) (D) 1.75 1.75 1.50 1.50 Final Volume, L 1.25 1.00 0.75 0.50 Final Volume, L 1.25 1.00 0.75 0.50 0.25 0.25 0.00 0.00 0.00 0.25 0.50 0.75 1.00 0.00 0.25 Volume O₂ added, L 0.50 0.75 1.00 Volume O₂ added, L 2arrow_forwardLeucine is an essential amino acid with the systematic name 2-amino-3-methylpentanoic acid. It has pai 2.36 and pKa2 = 9.60. H2N-C(R)H-COOH and R is -CH2-CH(CH3)2 A. Draw the condensed structure for leucine, and label all chirality centers with an asterisk. B. How many possible stereoisomers of leucine are there? C. Draw a Fischer projection of L-leucine and label the chirality center(s) as R or S. D. What is the p/ of leucine? E. Draw the structure of the predominant form of leucine at 10.00. F. Draw the structure of the predominant form of leucine at pH = 1.50. G. Leucine is described as an essential amino acid. What does this mean? H. Show the alkyl halide you would use to prepare leucine by the amidomalonate method. =arrow_forward
- a) Write out 6 completely different reactions of acetophenone (reagent, product). b) Write out 3 preparations of 1-methylcyclohexanol, using a different starting material for each one. You may use preps where you just change the functional group, and/or preps where you construct the carbon chain. c) Write out 3 preparations of 2-ethoxybenzoic acid, a different starting material for each one. You may use preps where you just change the functional group, and/or preps where you construct the carbon chain.arrow_forward12. CH3 OH OH H&C CH3 H₂C N OH H₂C CH3 H&C CH3 H₂C' CH3 H.C CH3OH H.C CH2CH3OH CH3CEN Which one of these 17 compounds is represented by this IR and this 'H NMR spectrum? IR Spectrum 3000 4000 3000 NMR Spectrum 2000 £500 RAVENUMBER 2000 1500 9 8 6 5 10 HP-00-290 ppm m 1000 500 1000 4 °arrow_forwardDraw the structure of (E,6R) 6-methoxy-4-hepten-2-one. Give the IUPAC name of this compound, including stereochemistry. Draw the most stable chair conformation of (cis) 1,3-isobutylcyclohexane. H HC=CCH₂ CH2CH3 EN(CH3)2 -CN(CH3)2arrow_forward
- 10. Write out the mechanism (intermediate/transition state) for this reaction; indicate stereochemistry in product. H3C CH₂OH CH3 SN1 Harrow_forwardWrite "most" under the member of each trio which is most stable. Write "least under the member of each trio which is least stable. b) Draw a Fischer projection of a pair of enantiomers with three chiral carbons. Which of these two would you expect to be more soluble in water? Why? 1-butanol 1-heptanol Which of these two would you expect to have the higher boiling point? Why? hexyl methyl ether 1-heptanolarrow_forwardWrite "most" under the most acidic compound. Write "least" under the least acidic compound. OH NO₂ OCH3 Br 9. Compound X, C50H84F2, reacts with excess H2/Pd to give a C50H88F2 compound. How many rings are in X? How many double bonds are in X? Show your work.arrow_forward
- 4. State whether these two are: a) the same molecule b) c) d) different compounds that are not isomers constitutional isomers diastereomers e) enantiomers CH3 CH₁₂ H OH HO H H OH HO H CH, CH₂ 5. a) How many stereocenters does this compound have? b) How many stereoisomers are possible for this compound? CH₂ OH CHCHarrow_forwardCalculating the pH at equivalence of a titration A chemist titrates 210.0 mL of a 0.1003 M hydrobromic acid (HBr) solution with 0.7550M KOH solution at 25 °C. Calculate the pH at equivalence. Round your answer to 2 decimal places. Note for advanced students: you may assume the total volume of the solution equals the initial volume plus the volume of KOH solution added. pH = ] ☑ o0o 18 Ararrow_forwardDo you do chemistry assignmentsarrow_forward
- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning
