The product of the claisen condensation of ethyl phenylacetate in the presence of sodium ethoxide ion has to be shown. Concept introduction: When two molecules of an ester undergo condensation, then it is called claisen condensation. Like in aldol reaction, in claisen condensation one molecule is a nucleophile and the other molecule is an electrophile. A claisen condensation reaction is a reversible reaction and occurs in the presence of a strong base. The first step of claisen condensation is the removal of a proton from alpha carbon by a base and then the addition of enolate ion formed to the second ester molecule forming a β-ketoester.

Question

Kumada Coupling: 1. m-Diisobutylbenzene below could hypothetically be synthesized by Friedel-Crafts reaction. Write out the reaction with a mechanism and give two reasons why you would NOT get the desired product. Draw the reaction (NOT a mechanism) for a Kumada coupling to produce the molecule above from m-dichlorobenzene. Calculate the theoretical yield for the reaction in question 2 using 1.5 g of p-dichlorobenzene and 3.0 mL isobutyl bromide. What signals appeared/disappeared/shifted that indicate that you have your intended product and not starting material? What other impurities are present in your product and how do you know?

Answer 1

Question

Chapter 19, Problem 19.29P

(a)

Interpretation Introduction

Interpretation:

The product of the claisen condensation of ethyl phenylacetate in the presence of sodium ethoxide ion has to be shown.

Concept introduction:

When two molecules of an ester undergo condensation, then it is called claisen condensation. Like in aldol reaction, in claisen condensation one molecule is a nucleophile and the other molecule is an electrophile.

A claisen condensation reaction is a reversible reaction and occurs in the presence of a strong base.

The first step of claisen condensation is the removal of a proton from alpha carbon by a base and then the addition of enolate ion formed to the second ester molecule forming a β-ketoester.

(b)

Interpretation Introduction

Interpretation:

The product of the claisen condensation of methyl hexanoate in the preesnce of sodium ethoxide ion has to be shown.

Concept introduction:

When two molecules of an ester undergo condensation, then it is called claisen condensation. Like in aldol reaction, in claisen condensation one molecule is a nucleophile and the other molecule is an electrophile.

A claisen condensation reaction is a reversible reaction and occurs in the presence of a strong base.

The first step of claisen condensation is the removal of a proton from alpha carbon by a base and then the addition of enolate ion formed to the second ester molecule forming a β-ketoester.

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