Please answer from \"How does the structure of the alkyl part of the alkyl halid
ID: 1035623 • Letter: P
Question
Please answer from "How does the structure of the alkyl part of the alkyl halide affect the reaction" to "nature of the nucleophile" please. (For both Sn1 and Sn2 reactions) thank you.
PRELAB EXERCISE: Predict the outcomes of the two sets of experiments to be carried out with the 11 halides used in this chapter e alkyl halides, R-X (where X - Cl, Br, I, and sometimes F), play a central role organic synthesis. These can easily be prepared from, among others, alcohols, enes, and, industrially, alkanes. In turn, they are the starting materials for the nthesis of a large number of new functional groups. The syntheses are often car- d out by nucleophilic substitution reactions in which the halide is replaced by other group such as cyano, hydroxyl, ether, ester, alkyl-the list is long. As a con- uence of the importance of this substitution reaction, it has been studied care- ly by employing reactions such as the two used in this chapter. Some of the estions that can be asked are as follows: How does the structure of the alkyl part of the alkyl halide affect the reaction? What is the effect of changing the . .. nature of the halide? nature of the solvent? SNISN relative concentrations of the reactants? temperature of the reaction? SN[4 SNZ nature of the nucleophile? SN2 this chapter, we explore the answers to some of these questions. In free radical reactions, the covalent bond undergoes homolysis when it eaks: © 2012, 2010 Cengage Learning ALL RIGHTS RESERVED. No part of this work covered by the copyright herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical Leaincluding but not limited to photocopying, recording. scanning, digitizing, taping, Web distribution 107 0
Explanation / Answer
Relative reactivity of structure of the substrate
SN2 Reaction decreasing order
Methyl> primary> secondary> Tertiary
SN1 Reaction decreasing order
Tertiary> secondary> Primary> methyl
Relative reactivity of structure of the substrate
SN2 Reaction decreasing order
Methyl> primary> secondary> Tertiary
SN1 Reaction decreasing order
Tertiary> secondary> Primary> methyl
Polar aprotic solvents favor the SN2 Reaction
Polar aprotic solvent: DMF, DMSO, Hexamethyl-Phosphoric triamide (HMPT)
The relative concentration of reactant
Relatively more concentrated nucleophiles favor the SN2 Reaction
Nature of nucleophile:
Nucleophilicity increasing going down to the group
I-> Br-> Cl-> F-
Nucleophilicity decreasing on going from left to right
NH3> H2O> F-