
(a)
Interpretation: The kind of sigmatropic rearrangement that occurs in each of the given reactions has to be given.
Concept introduction:
Pericyclic reactions are “ any concerted reaction in which bonds are formed or brocken in a cyclic transition state”. There is a single transition state from start to finish, in contrast to a stepwise reaction.
There are mainly three types of pericyclic reactions,
- 1) Electrocyclic reactions
- 2) Cycloaddition reactions
- 3) Sigmatropic reactions
In a sigmatropic reaction “ one new sigma-bond is formed as another breaks.”
Sigmatropic rearrangement reactions are named with digits. For example a [1, 3] sigmatropic rearrangement describe a reaction in which the residue migrates from position 1 to position 3.
(b)
Interpretation: Using arrows the electron rearrangement takes place in the given reactions has to be shown.
Concept introduction:
Pericyclic reactions are “ any concerted reaction in which bonds are formed or brocken in a cyclic transition state”. There is a single transition state from start to finish, in contrast to a stepwise reaction.
There are mainly three types of pericyclic reactions,
- 1) Electrocyclic reactions
- 2) Cycloaddition reactions
- 3) Sigmatropic reactions
In a sigmatropic reaction “ one new sigma-bond is formed as another breaks.”
Sigmatropic rearrangement reactions are named with digits. For example a [1, 3] sigmatropic rearrangement describe a reaction in which the residue migrates from position 1 to position 3.

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Chapter 28 Solutions
Organic Chemistry
- Q1: Answer the questions for the reaction below: ..!! Br OH a) Predict the product(s) of the reaction. b) Is the substrate optically active? Are the product(s) optically active as a mix? c) Draw the curved arrow mechanism for the reaction. d) What happens to the SN1 reaction rate in each of these instances: 1. Change the substrate to Br "CI 2. Change the substrate to 3. Change the solvent from 100% CH3CH2OH to 10% CH3CH2OH + 90% DMF 4. Increase the substrate concentration by 3-fold.arrow_forwardExperiment 27 hates & Mechanisms of Reations Method I visual Clock Reaction A. Concentration effects on reaction Rates Iodine Run [I] mol/L [S₂082] | Time mo/L (SCC) 0.04 54.7 Log 1/ Time Temp Log [ ] 13,20] (time) / [I] 199 20.06 23.0 30.04 0.04 0.04 80.0 22.8 45 40.02 0.04 79.0 21.6 50.08 0.03 51.0 22.4 60-080-02 95.0 23.4 7 0.08 0-01 1970 23.4 8 0.08 0.04 16.1 22.6arrow_forward(15 pts) Consider the molecule B2H6. Generate a molecular orbital diagram but this time using a different approach that draws on your knowledge and ability to put concepts together. First use VSEPR or some other method to make sure you know the ground state structure of the molecule. Next, generate an MO diagram for BH2. Sketch the highest occupied and lowest unoccupied MOs of the BH2 fragment. These are called frontier orbitals. Now use these frontier orbitals as your basis set for producing LGO's for B2H6. Since the BH2 frontier orbitals become the LGOS, you will have to think about what is in the middle of the molecule and treat its basis as well. Do you arrive at the same qualitative MO diagram as is discussed in the book? Sketch the new highest occupied and lowest unoccupied MOs for the molecule (B2H6).arrow_forward
- Q8: Propose an efficient synthesis of cyclopentene from cyclopentane.arrow_forwardQ7: Use compound A-D, design two different ways to synthesize E. Which way is preferred? Please explain. CH3I ONa NaOCH 3 A B C D E OCH3arrow_forwardPredict major product(s) for the following reactions. Note the mechanism(s) of the reactions (SN1, E1, SN2 or E2).arrow_forward
- (10 pts) The density of metallic copper is 8.92 g cm³. The structure of this metal is cubic close-packed. What is the atomic radius of copper in copper metal?arrow_forwardPredict major product(s) for the following reactions. Note the mechanism(s) of the reactions (SN1, E1, SN2 or E2).arrow_forwardPredict major product(s) for the following reactions. Note the mechanism(s) of the reactions (SN1, E1, SN2 or E2).arrow_forward
- Q3: Rank the following compounds in increasing reactivity of E1 and E2 eliminations, respectively. Br ca. go do A CI CI B C CI Darrow_forwardQ5: Predict major product(s) for the following reactions. Note the mechanism(s) of the reactions (SN1, E1, SN2 or E2). H₂O דיי "Br KN3 CH3CH2OH NaNH2 NH3 Page 3 of 6 Chem 0310 Organic Chemistry 1 HW Problem Sets CI Br excess NaOCH 3 CH3OH Br KOC(CH3)3 DuckDuckGarrow_forwardQ4: Circle the substrate that gives a single alkene product in a E2 elimination. CI CI Br Brarrow_forward
- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning
