Synthesize the following compound using only toluene as the carbon source- bis(3-methylphenyl)(phenyl)methanol

I have never done something like this before and I have no clue on how to start. I am even more confused by the fact that the top two phenyl groups are meta substituted despite having a methyl group which is suppose to be ortho and para directing.

From an answer below it states I need to use Friedel–Crafts acylation. However I am not entirely sure how to do this. This is my guess:

Convert toluene into benzoic acid using $\ce{KMnO4}$ and then react half of it with $\ce{SOCl2}$ to form $\ce{C6H5COCl}$. Then react that with the other half of the benzoic acid followed by Wolff–Kishner reduction to form the below molecule:

3-benzylbenzoic acid

After this, I am not sure how to chlorinate it so that I do another acylation.


2 Answers 2


An alternative approach might be something like this. The tertiary alcohol product with two identical groups suggests that a Grignard reaction with an ester might be a useful step.

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  • $\begingroup$ Looks good, except technically you were supposed to use toluene as the only carbon source so maybe you lose points esterifying the benzoic acid with methanol. Form an acyl chloride from the acid + SOCl2 instead, maybe? $\endgroup$ Commented May 1, 2020 at 19:49

You'll obviously need meta-directors, so convert those methyl groups into a different function.

I'd start with a benzylic oxidation to get benzoic acid, and work some Friedels-Craft acylation magic.

Then you can reduce the resulting ketone and chlorinate, and go at an acylation again.

Finally a DIBAL and then Wolf-Kichner Reduction to get rid of your carbonyls.

Probably you need to flesh this out some.

  • $\begingroup$ thanks for you answer. For the acylation step, do you mean that I need to convert toluene into benzoic acid using KMnO4 and then react half of it with SOCl2 to form C6H5COCl. Then react that with the other half of the benzoic acid? $\endgroup$
    – Nanoputian
    Commented Feb 21, 2016 at 5:35

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