A Grignard reaction involves which type of reagent reacting with a carbonyl compound?

A Grignard reaction involves which type of reagent reacting with a carbonyl compound?

• A. An organomagnesium halide
• B. An organomagnesium hydride
• C. An organomagnesium oxide
• D. An organomagnesium sulfate

Answer: (A)

Grignard reactions center on organomagnesium halides. These reagents, RMgX, are made when a halide reacts with magnesium in dry ether solvents. They are highly reactive toward carbonyl groups because the carbon attached to magnesium bears significant nucleophilic character. When an aldehyde or ketone encounters RMgX, the carbonyl carbon is attacked by the organic part (R), forming a tetrahedral alkoxide intermediate. After aqueous workup, this intermediate is protonated to yield an alcohol, with the exact product depending on the carbonyl compound used. The essential point is that the reactive species in a Grignard reaction is the organomagnesium halide, not hydrides, oxides, or sulfates of magnesium, which do not participate in the standard carbonyl addition pathway.

Grignard reactions center on organomagnesium halides. These reagents, RMgX, are made when a halide reacts with magnesium in dry ether solvents. They are highly reactive toward carbonyl groups because the carbon attached to magnesium bears significant nucleophilic character. When an aldehyde or ketone encounters RMgX, the carbonyl carbon is attacked by the organic part (R), forming a tetrahedral alkoxide intermediate. After aqueous workup, this intermediate is protonated to yield an alcohol, with the exact product depending on the carbonyl compound used. The essential point is that the reactive species in a Grignard reaction is the organomagnesium halide, not hydrides, oxides, or sulfates of magnesium, which do not participate in the standard carbonyl addition pathway.