Selective desaturation of amides: a direct approach to enamides

Abstract

A novel and regioselective N-α,β-desaturation and dehydrogenative N-β-halogenation of amides was developed. This chemistry with high selectivity and broad substrate scope provides an efficient approach to enamides from simple amides.

Photoexcited Palladium-Initiated Remote Desaturation of N-Alkoxypyridinium Salts

“…Great efforts toward the synthesis of this privileged functional group have been made via classic and effective methods . The direct desaturation of nonfunctionalized alkanes is arguably the most direct method for the introduction of a CC double bond into molecules due to atom and step economy. , Therefore, there have been some excellent evolutions in the direct desaturation of alkanes using transition metal catalysis . Although some desaturation reactions have been reported, the regioselective desaturation of nonactivated C–H bonds were relatively less explored .…”

Chiral Trifluoromethylated Enamides: Synthesis and Applicability

“…54 Recently, the groups of Maulide, Jiao and Xu presented a more direct approach by N-dehydrogenation of amides, which either requires strong oxidative conditions or superstoichiometric amounts of reagents and is limited to tertiary enamides. [55][56][57] Currently, synthetic strategies to access enamides with a stereogenic center, especially at the more challenging C𝛾-position, are scarce and the field is underexplored. Nevertheless, such compounds seem to be of interest as demonstrated by recent examples for the syntheses of axially chiral enamides.…”

Decarboxylative Enamide Synthesis from Carboxylic Acid and Alkenyl Isocyanate

“…For instance, many natural products with biological activity contain the enamide motif. − In addition, they are versatile synthetic intermediates and have found wide applications in asymmetric catalysis − and heterocycle synthesis . Classical pathways to enamides comprise the metal-catalyzed cross-coupling of amide NH with vinyl halide, − vinyl trifluoroborate, the addition of amide to alkyne, , isomerization of olefin, and other traditional procedures (Figure A). − Nonetheless, these established methods often require high temperature, special substrates that need multistep synthesis, limited substrate scope, and expensive catalysts and ligands.…”