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7 Cards in this Set

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Treatment of an aldehyde or ketone with a Grignard reagent,RMgX,yields....
an alcohol by nucleophilic addition of a carbon anion, or carbanion
A carbon-magnesium bond is strongly polarized, so a Grignard reagent reacts for all practical purposes...
as R:-+MgX
A grignard rxn begins with....... thereby making the carbonyl group .....
- an acid-bases complexation of Mg+2 to the carbonyl oxygen atom

- a better leaving electrophile.
In the Grignard Rxn's 2nd step is where a Nucleophilic addition of R:- produces a ...
tetrahedral magnesium alkoxide intermediate, and protonation by addition of water or dilute aqueous acid in a separate step yields the neutral alcohol
Unlike the nucleophilic addition of water and HCN, Grignard additions are irreversible because . .
a carbanion is too poor a leaving group to be expelled in a reversal step
Just as addition of a Grignard reagent to an aldehyde or ketone yields
- an alcohol, so does addition of hydride ion,:H
In an addition of a Grignard reagent to an aldehyde or ketone, LiAlH and NaBH4 act as if they were donors of hyride ion in a nucleophilic addition rxn. Addition of water or aqueous acid after the hyride addition step protonates
the tetrahedral alkoxide intermediate and gives the alcohol product