In 1981, Weinreb and Nahm obtained ketones by adding lithium or magnesium organometallics to N-methyl-N-methoxyamides.
Weinreb's amides are prepared from acid halides or anhydrides by reaction with N,O-dimethylhydroxylamine in the presence of base (pyridine).
weinreb synthesis 01
weinreb synthesis 02
Weinreb's amide can be reduced with DIBAL yielding the corresponding aldehyde.
weinreb synthesis 03
It is also possible to obtain Weinreb's amide from esters and lactones, catalyzing the reaction with a Lewis acid such as trimethylaluminium.
weinreb synthesis 04
Amide formation:
weinreb synthesis 05
Reaction with organometallic:
weinreb synthesis 06