Kaplan Friedel-Crafts Problem

[Needalittlehelp]

---

Members do not see this ad.

This is a Kaplan problem (OChem Subject Test 3, number 14):

Which monosubstitution product(s) would be expected from the following reaction?

Acetophenone + Br2, FeBr3

The solution says that the Br adds to the position meta from the COCH3. However, I thought that Friedel-Crafts reactions couldn't occur if the benzene ring is substituted with the following (according to McMurry's Organic Chemistry): NR3+, NO2, CN, SO3H, CHO, COCH3, CO2CH3, NH2, NHR, or NR2.

Could this have been an oversight on Kaplan's part or is there something I'm missing?

 

[Troyvdg]

This might clarify things. Acylation and Alkylation will not occur if the ring is STRONGLY deactivated, so you are correct there (this would include all deactivating groups but halogens). However, this isn't a Friedel-Craft reaction. This is just an electrophilic aromatic substitution 👍

 

[Needalittlehelp]

Okay, so the reaction I've shown isn't Friedel-Crafts? I'm a bit confused because in my textbook they seem to be right next to each other. Is this not Friedel-Crafts because the reagent is Br2, FeBr3, and Friedel-Crafts should be R-X, AlCl3/FeBr3/etc or R-CORX/AlCl3/etc?

 

[Needalittlehelp]

That last reagent should say *RCOX/AlCl3

 

[Troyvdg]

Okay, so the reaction I've shown isn't Friedel-Crafts? I'm a bit confused because in my textbook they seem to be right next to each other. Is this not Friedel-Crafts because the reagent is Br2, FeBr3, and Friedel-Crafts should be R-X, AlCl3/FeBr3/etc or R-CORX/AlCl3/etc?

Correct. this is not Friedel-Crafts. if it was R-X FeBr3/AlCl3, then it would be a Friedel-Craft alkylation.

 

[Needalittlehelp]

Thank you so much!