Willgerodt reaction amide synthesis

The Willgerodt reaction allows amide synthesis from aromatic aldehydes or ketones, using a secondary amine and a thiating agent. The mechanism of the more convenient Kindler modification, employing sulfur and morpholine, has been reviewed.281... 

The Willgerodt Reaction allows the synthesis of amides from aryl ketones under the influence of a secondary amine and a thiating agent. The mechanism involves the formation of an enamine which undergoes thiation, and the carbonyl group migrates to the end of the chain via a cascade of thio-substituted iminium-aziridinium rearrangements. 

The Willgerodt-Kindler reaction has been used to synthesize O-methyldauri-cine (17). The product was evidently a mixture of diastereomers (272-274). A similar approach provided stebisimine (409), obaberine (80), and isotetrandrine (236) (275). In a variation, enamine thioether 410 reacted with 411 to generate bis amide intermediates for the synthesis of 80, 236, and 409 (276). 

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