91影视

Isotope labeling is a technique used in the 鈥渋nvestigation of rhe mechanism鈥� of the chemical reaction.

E.g.,Hydrolysis of ester, when carried out withlabeled oxygen $\left({}^{18}\mathbf{O}\right)$, results in the formation of alcohol with labeled oxygen atoms which concludes that the 鈥渃leavage of the alkyl - Oxygen鈥� bond has occurred.

The nucleophile addition reaction of the water on the ketone/aldehyde is shown as follows:

Labeled oxygen ${}^{\text{18}}\text{O}$(represented by *)

Nucleophile addition reaction

The steps that involve nucleophile addition of water (neutral nucleophile) on the carbonyl carbon of aldehyde or ketone are all reversible.

As all the steps are reversible, the mechanism of nucleophile addition on the carbonyl carbon, the reverse mechanism, can be shown, responsible for incorporating labeled oxygen ${}^{\text{18}}\text{O}$(represented by *) on the carbonyl carbon.

The reverse reaction of nucleophile addition of water in aldehyde/ketone is shown as follows:

Reverse nucleophile addition reaction