NHC-catalyzed [3 + 3] cycloaddition of α-bromoenals with nitroketene aminals or nitroketene N,S-acetals: synthesis of nitro-containing dihydropyridin-2-ones

Abstract

An efficient N-heterocyclic carbene (NHC)-catalyzed [3 + 3] cycloaddition of α-bromoenals with β-nitro enamines has been developed. This methodology provides an efficient strategy for the construction of valuable nitro-containing heterocyclics....

NHC‐Catalyzed Enantioselective Transformations Involving α‐Bromoenals

“…In general, the mechanism involved the nucleophilic attack of NHC ). [38] α-bromoenals containing either electron-donating, or electron-withdrawing at para-, meta-, or ortho-positions of the phenyl ring showed good compatibility in this reaction. In addition to aromatic bromoenals, aliphatic bromoenals also were workable under theses organocatalysis conditions.…”

Asymmetric synthesis of chiral pyrazolo[3,4-b]pyridin-6-ones under carbene catalysis

“…N-Heterocyclic carbene catalysis reactions have proven to be some of the most efficient asymmetric catalysis reactions. 5 Among them, NHC-catalyzed asymmetric [3 + 3] annulation 6 of unsaturated acyl intermediates with enamines I–XIII 7–19 is identified as one of the most efficient methods for the synthesis of δ-lactams with acceptable outcomes (Fig. 1b).…”