13P - Organic Chemistry (Mcmurry)

Question

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

 

Step-by-Step Solution

Answer

Step 1: 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

Step 2: Conclusion

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

Step 3: 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

Step 4: Conclusion

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