Mastering Organic Chemistry: Nucleophiles and Reaction Mechanisms
School
Lahore University of Management Sciences, Lahore**We aren't endorsed by this school
Course
CHEM 231
Subject
Chemistry
Date
Dec 11, 2024
Pages
4
Uploaded by DoctorFreedomGuanaco51
CHEM-231: Fundamentals of Organic ChemistryStudent ID:----------------Assignment 2 (Submission deadline: Nov. 18, 2024)Total marks:56Q1. List the following species in order from the best nucleophile to the poorest nucleophile in anaqueous solution.(2)Q2. a) Rank the following series of molecules based on reactivity in an SN2 reaction (NaI/acetone).(1= fastest SN2, 4= slowest SN2)(2)b) Rank the following series of molecules based on reactivity in an SN1 reaction (EtOH/heat).(1= fastest SN1, 4= slowest SN1)(2)c) Rank the following series of molecules based on reactivity in an E2 reaction (NaOiPr/iPrOH) andgive a justification for the slowest E2 reaction. (1= fastest E2, 4= slowest E2)(4)Q3. For each of the following reactions, figure out the frontiers orbital interaction when nucleophileattacks an electrophile and their type of interaction. Draw all the lone pairs and use curved arrows toshow how the nucleophile attacks the electrophiles and show the product of this one step reactions. (8)
Q4. Predict which of the following two compounds will undergo an E2 reaction more rapidly andexplain your answer.(3)Q5. The following tertiary alkyl halide was heated in ethanol for several days, and the resultingmixture of products contained five different elimination products and two substitution products.(a) Draw the substitution products and identify the relationship between them.(2)(b) Identify which substitution product is expected to be favored and explain your choice. (2)(c) Draw all of the elimination products, and identify which products are stereoisomers.(2)(d) For each pair of stereoisomeric alkenes, identify which stereoisomer is expected to be favored.(2)Q6.Consider the reaction of 2-bromo-4-tert-butylcyclohexanol upon treatment with sodium amide(NaNH2). In boxes 2 and 3, draw the structures of the intermediate and product of this reaction,respectively. Draw the curved arrows to show the flow of electrons for each step. Also determine thefrontier orbitals interaction and the type of their interaction for each curved arrow that you draw forthe 2ndstep (SN2) reaction.(3)Q7. Which isomer (cis or trans) of 1-bromo-4-isopropylhexane drawn below reacts faster in an E2reaction? Explain your choice by drawing the chair confirmation of both the stereoisomers withappropriate position of groups required for E2 elimination.(5)
Q8. Which of the following products (A or B) is less likely to be formed by E1 reaction. Provide thereaction conditions and the mechanism of the formation of only one possible product. (4)Q9. What will be the product of the following react, draw its structure with correct stereochemistry.Give a proper mechanism for the reaction clearly showing the major product formed. Draw itsreaction coordinate diagram and indicate the frontier orbitals interaction and their type of interactionin the rate determining step.(5)Q10. Consider the substrate 2-bromoethyl ethyl ether (Br-CH-CH-OEt). In the presence of₂₂a nucleophile, the oxygen atom on the ether group can participate in the reaction pathway,forming a three-membered oxonium ion intermediate after the bromine leaves. Thenucleophile then attacks this intermediate. Predict the product that results from thenucleophilic attack on the oxonium ion intermediate. Explain whether the reaction results inretention or inversion of configuration at the carbon centre. (5)Q11. What is the major elimination product obtained from an E2 reaction of each of thefollowing alkyl halides with hydroxide ion? (draw their chair form for mechanism). (5)
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