[kindaichibkk]

The question is to find the products and mechanisms of the reaction.
My problem is, I don't know in which postion that electrophilic reaction to form molozonide would take place?
Would it be position 1 or 2 or in both position? and why?

Thank you so much in advance for all your help

Ps. I missed type the amount of O3. Actually it should be 1eq of O3

[dexangeles]

I'm not sure about this but I believe it should react at both sides....

let's see what the mods and admins say about this, im curious now too

[Demotivator]

My guess is both sites react to produce:
CH3-O-COCH2-CHO  +  HCO-CH2-COCH3

[Mitch]

Demotivator is most likely right. Try adding just 1 eq of O3 in practice, its not going to happen. You have to bubble it through the solution.

[Demotivator]

Oh, now I'm less certain. 1 equiv might limit reactivity to one site.

[Mitch]

Yeah but actually adding only 1 equivalent would be more complicated then trying to figure out where it would react first.  

[movies]

O₃ behaves as an electrophilic reagent so it will react at position 1 first since it is a more electron rich alkene.  I've been told you can actually get pretty decent selectivity in these situations.

[kindaichibkk]

Thanks so much everyone for your helpful discussions
Actually, I thought as what movies said but wasn't so sure
If we put only 1eq of ozone, it would select to react at only one site and it'd be at position 1
But still, I don't understand why position 1 si more electron rich than 2?
Because as I remember, CH3 group donate also electrons.
and in some cases, like ketone group who has also an atome of oxygen, they are electron attractors

 

Anyway, the argument from Mitch is also interesting.
Practically it'd be difficult to limit the amount of O3 to 1 eq
hmmm ... maybe I should ask my teacher today for this point,
even it's monday morning  

Thanks again. And if I have any further infos concerning this question, I will reply

[movies]

An ether like CH₃O- is a much better electron donor than CH₃- because the donation comes from lone pairs instead of bonds.  The lone pairs are considerably higher energy and therefore more available for donation.

In the case of a ketone the effect is reversed, but then you have a carbon in between the oxygen and the alkene.  So in that case the resonance structure points the other direction.