Organic chemistry

[Gholam2020]

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Question 209, 2017
The question is Gilman and it will attack conjugated ketone on beta position that i understood. My only question is the Michael reaction does the same thing with only difference is the enolate as an intermediate. The question is what is mechanism behind Gilman reagent? If you have conjugate Ketone with one side more substituted than other side? which side does Gilman attack?
Thanks in advance

 

[DAT Destroyer]

Question 209, 2017
The question is Gilman and it will attack conjugated ketone on beta position that i understood. My only question is the Michael reaction does the same thing with only difference is the enolate as an intermediate. The question is what is mechanism behind Gilman reagent? If you have conjugate Ketone with one side more substituted than other side? which side does Gilman attack?
Thanks in advance

The Gilman reagent will attack the beta carbon when reacted with conjugated carbonyls. The Gilman reagent will react in a nucleophilic-like fashion to attack the beta carbon, as any nucleophile would do in a typical Michael Reaction. The reaction is heavily guided under orbital control, hence the carbonyl group does not react. Simply attack the beta carbon . If you used a dimethylcuprate as the Gilman,,,,,,just simply attack it with CH3 -.....a nucleophile. Since we are treating this reaction as a nuclephilic reaction-type, attack the LESS sterically hindered side.

I hope this help.

Dr. Romano

 

[Gholam2020]

Thanks Dr, Romano so it is simply do to Steric Hinderic that gilman attack less substituted side. Amazing explanation as always