After all the reactions you’ve seen by now of the carbonyl group with different nucleophiles, it’s easy to fall into the trap of assuming that the same thing goes for carboxylic acids.
But they’re an important exception to be aware of when it comes to their reactions with Grignard reagents.
Grignard reagents are strong bases… so when then meet a carboxylic acid, the first thing that happens is that they get protonated (i.e. destroyed). So Grignard reagents don’t add to carboxylic acids.
Watch out for this! It comes up a lot.
Tomorrow: let’s wrap up the week.
Thanks for reading! James
P.S. Further reading – Carboxylic Acids Are Acids