Reactions

An initial activation step is required to activate the carboxylic acid, typically through formation of an acyl chloride or an active ester. Then, a nucleophilic addition-elimination is performed by DMHA onto the electrophilic carbonyl carbon of the activated carboxylic acid species, leading to the expulsion of the leaving group to give a protonated ammonium intermediate. The introduction of a base then promotes deprotonation of this ammonium intermediate, generating the Weinreb amide.
This special amide is useful to perform a controlled, single-step conversion into an aldehyde in the presence of lithium aluminium hydride (LiAlH₄), thanks to the chelation-stabilized tetrahedral intermediate that prevents over-reduction to the primary alcohol.