Question

Question: What alkyl halides would you use to prepare the following ketones by an acetoacetic ester synthesis?

Short answer

The alkyl halides which you need to use to prepare ketone (a) is 1-bromo-2-methylpropane.

The product of this reaction is

Hence, the$-C{H}_{2}COC{H}_3$comes from acetoacetic ester.

The remaining part ${\left(C{H}_3\right)}_{2}CHC{H}_2$ comes from alkyl halide (1-bromo-2-methylpropane).

Now the mechanism of this reaction is

Step-by-step solution

Subpart (a)

The alkyl halides which you need to use to prepare ketone (a) is 1-bromo-2-methylpropane.

The product of this reaction is

Hence, the$-C{H}_{2}COC{H}_3$comes from acetoacetic ester.

The remaining part ${\left(C{H}_3\right)}_{2}CHC{H}_2$ comes from alkyl halide (1-bromo-2-methylpropane).

Now the mechanism of this reaction is

Conclusion

The alkyl halide which you need to use to prepare the given ketone (a) by acetoacetic ester is 1-bromo-2-methylpropane.

Subpart (b)

The alkyl halides which you need to use to prepare ketone (b) is 1-bromo-2-phenylethane.

The product of this reaction is

Hence, the –CH₂COCH₃ comes from acetoacetic ester.

The remaining part C₆H₅CH₂CH₂- comes from alkyl halide (1-bromo-2-phenylethane).

Now the mechanism of this reaction is

Conclusion

The alkyl halide which you need to use to prepare the given ketone (b) by acetoacetic ester is 1-bromo-2-phenylethane.