Q11P - Organic Chemistry (Mcmurry)

Question

Imine formation is reversible. Show all the steps involved in the acid-catalyzed reaction of an imine with water (hydrolysis) to yield an aldehyde or ketone plus primary amine.

Step-by-Step Solution

Answer

                                                   Protonation of imine

                                               Formation of oxonium ion

                                           Formation of ammonium ion

                                              Formation of protonated carbonyl

                                         Formation of desired product

Step1: Imine formation

Imine formation is a nucleophilic addition of a primary amine to the carbonyl group of aldehyde or ketone. Followed by proton transfer to form neutral amino alcohol.

Step 2: Acid-catalyzed reaction

In the acid-catalyzed hydrolysis of an imine, the first step is the protonation of the imine to form an iminium ion.

                                                Protonation of imine

Next, $H_{2}O$ attacks on the iminium ion forms an oxonium ion

                                         Formation of oxonium ion

                                                    Formation of oxonium ion

Formation of ammonium ion by the shift of proton

                                       Formation of ammonium ion

Formation of protonated carbonyl takes place by the removal of primary amine by the hydroxyl group.

                                       Formation of protonated carbonyl

Finally, the proton attached to carbonyl has lost to give the final product.

                                       Formation of desired product