Thursday, May 19, 2011

REACTION OF RMgX WITH AN NITRILE

Step 1:
The nucleophilic C in the organometallic reagent adds to the electrophilic C in the polar nitrile group. Electrons from the CยบN move to the electronegative N creating an intermediate imine salt complex.
addition of Grignard reagent to an nitrile
Step 2:
An acid/base reaction. On addition of aqueous acid, the intermediate salt protonates giving the imine.
Step 3:
An acid/base reaction. Imines undergo nucleophilic addition, but require activation by protonation (i.e. acid catalysis)
Step 4:
Now the nucleophilic O of a water molecule attacks the electrophilic C with the p bond breaking to neutralize the change on the N.
Step 5:
An acid/base reaction. Deprotonate the O from the water molecule to neutralize the positive charge.
Step 6:
An acid/base reaction. Before the N system leaves, it needs to be made into a better leaving group by protonation.
Step 7:
Use the electrons on the O in order to push out the N leaving group, a neutral molecule of ammonia.

Step 8:
An acid/base reaction. Deprotonation reveals the carbonyl group of the ketone product.

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