Rearrangements in grignards?

[510586]

Is there ever rearrangement in grignards similar to friedalcrafts with 3 or more carbons (though grignards is nuc not electrophile)?

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[Dental_14]

No I don't think so, Gring. is a strong base and will most likely do SN2 attack. Unless it's doing a nucleophilic addition like it does with aldehydes.
Pretty sure no rearrangements because we only see those with SN1 and E1

 

[zEkii]

I think of grignard's reagent as a very strong base reaction(nucelophilic).But what follows with the reagent is an acid catalyzed solution. But, if a strong base is with a non acidic solution(ether, or methanol), then rearrangement can occur. That is one of the unique features with grinards, is that it is able to play with a really acidic solution.

 

[510586]

I think of grignard's reagent as a very strong base reaction(nucelophilic).But what follows with the reagent is an acid catalyzed solution. But, if a strong base is with a non acidic solution(ether, or methanol), then rearrangement can occur. That is one of the unique features with grinards, is that it is able to play with a really acidic solution.

Do you have any example of this rearrangement

 

[zEkii]

Do you have any example of this rearrangement

http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/rearang2.htm

 

[510586]

So a grignard can add a humongously long chain unlike friedalcrafts alkylation correct?

 

[zEkii]

Yup, if it was like... decaneMgBr. It can definitely add it in there, with H3O+ of course

 

[DAT Destroyer]

Is there ever rearrangement in grignards similar to friedalcrafts with 3 or more carbons (though grignards is nuc not electrophile)?

Grignards rarely EVER do any rearrangements......For your purposes......NEVER !!!!! Why ? Grignards do not participate in carbocation mechanisms.....and would likely not rearrange. Friedel Craft reactions involve carbocations many times....and in the case of Friedel Craft alkylations, rearrangements are common.

Hope this helps

Dr. Romano

 

[510586]

Grignards rarely EVER do any rearrangements......For your purposes......NEVER !!!!! Why ? Grignards do not participate in carbocation mechanisms.....and would likely not rearrange. Friedel Craft reactions involve carbocations many times....and in the case of Friedel Craft alkylations, rearrangements are common.

Hope this helps

Dr. Romano

Ah OK I got confused. Thanks