16P - Organic Chemistry (Mcmurry)

Question

Show how you might prepare the following compounds using an alkylation reaction as the key step:

Step-by-Step Solution

Answer

Step 1: (a) Explanation of Alkylation reaction

In alkylation reaction, a methyl or a primary alkyl group is introduced to a ketone or ester or nitrile through a S_N² substitution reaction with the help of an enolate ion and alkyl halide. The enolate ion produced from the LDA.

 

Step 2: Mechanism of the reaction

Step 3: Explanation of the solution

In this reaction, a methyl group is introduced to the partially positive charged position of 1-phenylpropane-2-one. Treating with LDA, the ketone becomes enolate ion. Then the enolate ion attacks the methyl bromide and eliminates the bromide ion and produces the desired product.

Step 4: Conclusion

Therefore the preparation of 3-phenylbutan-2-one from 1-phenylpropane-2-one using alkylation reaction is like

Step 5: (b) Explanation of Alkylation reaction

In alkylation reaction, a methyl or a primary alkyl group is introduced to a ketone or ester or nitrile through a S_N² substitution reaction with the help of an enolate ion and alkyl halide. The enolate ion produced from the LDA.

Step 6: Mechanism of the reaction

Step 7: Explanation of the solution

In this reaction, an ethyl group is introduced to the partially positive charged position of pentanenitrile. Treating with LDA, the nitrile becomes enolate like ion. Then the enolate like ion attacks the ethyl iodide and eliminates the iodide ion and produces the desired product.

 

Step 8: Conclusion

Therefore the preparation of 2-ethylpentane nitrile from pentanenitrile using alkylation reaction is like

Step 9: (c) Explanation of Alkylation reaction

In alkylation reaction, a methyl or a primary alkyl group is introduced to a ketone or ester or nitrile through a S_N² substitution reaction with the help of an enolate ion and alkyl halide. The enolate ion produced from the LDA.

Step 10: Mechanism of the reaction

Step 11: Explanation of the solution

In this reaction, an allyl group is introduced to the partially positive charged position of cyclohexanone. Treating with LDA, the ketone becomes enolate ion. Then the enolate ion attacks the allyl iodide and eliminates the iodide ion and produces the desired product.

 

Step 12: Conclusion

Therefore the preparation of 2-allylcyclohexanone from cyclohexanone using alkylation reaction is like

Step 13: (d) Explanation of Alkylation reaction

In alkylation reaction, a methyl or a primary alkyl group is introduced to a ketone or ester or nitrile through a S_N² substitution reaction with the help of an enolate ion and alkyl halide. The enolate ion produced from the LDA.

Step 14: Mechanism of the reaction

Step 15: Explanation of the solution

In this reaction, a four methyl groups are introduced to the two partially positive charged position of cyclohexanone. Treating with excess LDA, the ketone becomes enolate ion by eliminating the four Hydrogens in it. Then the enolate ion attacks the methyl iodide and eliminates the iodide ion and produces the desired product.

Step 16: Conclusion

Therefore the preparation of 2,2,6,6-tetramethylcyclohexanone from cyclohexanone using alkylation reaction is like

Step 17: Explanation of Alkylation reaction

In alkylation reaction, a methyl or a primary alkyl group is introduced to a ketone or ester or nitrile through a S_N² substitution reaction with the help of an enolate ion and alkyl halide. The enolate ion produced from the LDA.

 

Step 18: Mechanism of the reaction

Step 19: Explanation of the solution

In this reaction, a methyl group is introduced to the partially positive charged position of ethyl phenyl ketone. Treating with LDA, the ketone becomes enolate ion. Then the enolate ion attacks the methyl iodide and eliminates the iodide ion and produces the desired product.

 

Step 20: Conclusion

Therefore the preparation of isopropyl phenyl ketone from ethyl phenyl ketone using alkylation reaction is like

Step 21: (f) Explanation of Alkylation reaction

In alkylation reaction, a methyl or a primary alkyl group is introduced to a ketone or ester or nitrile through a S_N² substitution reaction with the help of an enolate ion and alkyl halide. The enolate ion produced from the LDA.

 

Step 22: Mechanism of the reaction

Step 23: Explanation of the solution

In this reaction, an ethyl group is introduced to the partially positive charged position of methyl-3-methylbutanoate. Treating with LDA, the ester becomes enolate ion. Then the enolate ion attacks the ethyl iodide and eliminates the iodide ion and produces the desired product.

Step 24: Conclusion

Therefore the preparation of methyl-2-ethyl-3-methylbutanoate from methyl-3-methylbutanoate using alkylation reaction is like