The acid-catalysed reaction of hydrogen azide with electrophiles, such as carbonyl compounds, tertiary alcohols or alkenes. After a rearrangement and extrusion of N2, amines, nitriles, amides or imines are produced.
Mechanism of the Schmidt Reaction
Reaction of carboxylic acids gives acyl azides, which rearrange to isocyanates, and these may be hydrolyzed to carbamic acid or solvolysed to carbamates. Decarboxylation leads to amines.
The reaction with a ketone gives an azidohydrin intermediate, which rearranges to form an amide:
Alkenes are able to undergo addition of HN3 as with any HX reagent, and the resulting alkyl azide can rearrange to form an imine:
Tertiary alcohols give substitution by azide via a carbenium ion, and the resulting alkyl azide can rearrange to form an imine.
Reactions of Alkyl Azides and Ketones as Mediated by Lewis Acids: Schmidt and Mannich Reactions Using Azide Precursors
P. Desai, K. Schildknegt, K. A. Agrios, C. Mossman, C. Mossman, G. L. Milligan, J. Aubé, J. Am. Chem. Soc., 2000, 122, 7226-7232.