[kidd101]

hi,
I'm having problem with bezene reactions and one specific rxn i don't understand how it is wrong is this:

if you could briefly explain me why this is wrong and what would be the mechanism of the correct one so i can understand the concept of it.

thank you.

[nj_bartel]

What class of substitution reaction is that?  What's the ideal substrate for that reaction?  Why?

[g-bones]

I admit that looks like an enticing answer, but there maybe a driving force for another type of reaction and product.  also look at the mechanism of what you have and see if you can identify any problems that may arrive or raise the energy of the ts

[Agent-X]

Is this an E2 reaction that creates an alkene group?
The NaOH acts as a strong base, which causes dehydrogenation?

Sorry if I'm screwing with the pedagogy here. I need practice.

[g-bones]

I would argue that this may in fact be an E1 reaction seeing as its placing a carbocation in a tertiary carbon and is in the benzylic position.  either way elimination would create a conjugated system, which would be favorable

[Agent-X]

I would argue that this may in fact be an E1 reaction seeing as its placing a carbocation in a tertiary carbon and is in the benzylic position.  either way elimination would create a conjugated system, which would be favorable

I don't see that. I don't agree.

Benzylic halides undergo base catalysed dehydrohalogenation via an E2 pathway to form conjugated alkenes

source: http://www.chem.ucalgary.ca/courses/350/Carey5th/Ch11/ch11-9-4.html

[g-bones]

I stand corrected, it looks like you are right and under basic conditions its E2.  I just saw that a benzylic carbocation would be especially stable, especially since it is tertiary too. 

[macman104]

It is true that the carbocation at the position would be very stable, however you are in very basic conditions, so it is not advised to draw a positive charge in the reaction mechanism.  E1 reactions are typically acidic eliminations like acid catalyzed dehydration, because the conditions would support the formation of a positive charge.

[ufalynn88]

It's SN2, not E2 as there is no elimination occuring...and it isnt possible because SN2 cannot occur on tertiary carbons.