Help!

[motivated dent]

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ok just want to make sure a few things are clear. in SN2 reactions the reaction can go to sp3-->sp2 right? also for friedel crafts acylation and alklaytion it wont' add to a compound that deactivating right?

 

[iwannabadentist]

as far as i know...both of those things are false! SN2 cannot go from sp3 --> sp2! in order for that to happen...you would need an alkane (sp3) to go to an alkene (sp2) which only happens with E1 and E2 (elimination). Also...Friedel crafts will add to deactivating group in meta position as long as you have AlCl3 or FeBr3 (depending on what you alkyl halide you have). Hope that helps!

 

[drillbit]

SN2 rxns go from sp3 --> sp2 --> sp3 - the sp2 stage respresents the transition state!

 

[illbirz]

Remember Sn2...is a 2nd order substitution. One substitutent leaves and one comes instead. which would mean that the main atom(usually Carbon) will have its 4 bonds attached to it which makes a sp3. But in the case of E1 you get substituent to leave making a carbo cation (a positive charge carbon) which then gets electrons from its neighboring carbons to form a double bond. When the atom in this case the carbon has 3 bonds attached to it, you get a sp2 which goes to show that only sp2 is formed only with e1 or E1.

Hope it helped.

 

[illbirz]

as far as i know...both of those things are false! SN2 cannot go from sp3 --> sp2! in order for that to happen...you would need an alkane (sp3) to go to an alkene (sp2) which only happens with E1 and E2 (elimination). Also...Friedel crafts will add to deactivating group in meta position as long as you have AlCl3 or FeBr3 (depending on what you alkyl halide you have). Hope that helps!

One tid bit of extra info here is that, halides which are electron withdrawing(deactivating) atoms form ortho/para positions.

 

[drillbit]

In SN2 rxns - the nucleophile attackes the compound and displaces the leaving group simultaneously forming a pentacoordinate transistion state that is approx sp2 hybridized. When the LG leaves it goes back to sp3. So the product will be sp3. i just wanted to clarify - I was a bit vague in my explanation.......🙂

 

[joonkimdds]

I am pretty sure I read this question about sp3 from either kaplan or destroyer...i forgot which material had that question. Where did u get that question from?