JEE WhatsApp Group
Sign in
Please select an account to continue using cracku.in
↓ →
JEE WhatsApp Group
Join Our JEE Preparation Group
Prep with like-minded aspirants; Get access to free daily tests and study material.
This reaction is a textbook Cannizzaro Reaction (self oxidation-reduction of aldehydes lacking α-hydrogens). Here is the precise step-by-step pathway showing why the deuterium ends up on the oxygen and not the carbon atom.
The deuterated hydroxide ion (OD¯) acts as a nucleophile and attacks the electrophilic carbonyl carbon of the first benzaldehyde molecule. This pushes the π-electrons up onto the carbonyl oxygen, forming a tetrahedral intermediate.
The tetrahedral intermediate reformulates its carbonyl stable double bond. In doing so, it expels a hydride ion (H¯). This hydride shifts directly to a second molecule of benzaldehyde.
Note: Because this is a direct intermolecular transfer, the hydride never mixes with the solvent, meaning no deuterium can bind to this central carbon.
The generated carboxylic acid is highly acidic, and the alkoxide intermediate is a strong base. Rapid acid-base proton/deuteron exchange occurs instantly with the deuterated solvent (D2O) or directly between them to form stable final products.
As demonstrated by the electron tracking arrows:
Therefore, the carbon maintains two normal H atoms, while the oxygen captures the OD variant.
Create a FREE account and get:
Educational materials for JEE preparation
Ask our AI anything
AI can make mistakes. Please verify important information.
AI can make mistakes. Please verify important information.
