Acid Chloride Reactions: Ketone formation using Gilmans Reagents

Acid chlorides react with organometallic molecules known as Gilman reagents to form ketones. These molecules are typically composed of a copper atom (Cu), a lithium atom (Li), and two identical alkane chains (R2):

The alkane chains can be variable in length however, both chains must be the same. The chains can be as small as methyl groups and even as large as cyclohexane groups:

Methyl Group Example

Cyclohexane Group Example

The reaction mechanism is depicted below:

In the first step, the bond between one alkyl group (R) and copper (Cu) is broken, sending its electrons to form a bond with the carbonyl carbon. This then breaks the double bond with oxygen, sending the electrons from the bond up to the oxygen atom.

In the second step, the electronegative oxygen reestablishes its double bond with the carbon atom, kicking the chloride ion off.

The byproducts of this reaction are lithium chloride (LiCl) and an organocopper molecule (RCu). This reagent only works on acid chlorides and not ketones, which is why the reaction does not proceed a second time when encountering the ketone product.

Practice this reaction using our Reaction Solver!