Rhodium-Catalyzed N-Arylation of 2-Pyridones Enabled by 1,6-Acyl Migratory Rearrangement of 2-Oxypyridines

Gold(I)-catalyzed synthesis of N-alkenyl 2-pyridonyl sec-amines

N-Alkenyl 2-pyridonyl amines are afforded in high yields via a gold-catalyzed rearrangement of 2-propargyloxypyridine and 2-(but-3-yn-1-yloxy)pyridine under acidic conditions. This approach exhibits significant utility due to its outstanding efficiency of conversion in the synthesis of secondary amines as a one-pot reaction. The initial step of the method involves a cyclization reaction for the production of pyridinium salts, followed by the next stage, where rearrangement is accomplished through the nucleophilic addition phenomenon. This approach provides the conversion of primary amines into secondary amines, resulting in a single product. Furthermore, the methodology presents a high degree of tolerance towards several pyridine and aniline derivatives, resulting in the formation of products with excellent yields.

Iridium-catalyzed asymmetric cascade dearomative allylation/acyl transfer rearrangement: access to chiral N-substituted 2-pyridones

Iridium-catalyzed dearomative allylation/acyl transfer rearrangement has been developed using easily available 2-pyridinyl benzoates and vinyl ethylene carbonate. This protocol enabled the expedient synthesis of a variety of chiral N-substituted 2-pyridones in good to high yields with excellent enantioselectivity. It has the advantages of high atom economy, wide substrate scope, gram-scale synthesis, and versatile synthetic transformations.

Rh(II)-catalysed N2-selective arylation of benzotriazoles and indazoles using quinoid carbenes via 1,5-H shift

An efficient Rh(II)-catalyzed highly selective N2-arylation of benzotriazole, indazole, and 1,2,3 triazole is developed using diazonaphthoquinone. The developed protocol is extended with a wide scope. In addition, late-stage arylation of these scaffolds tethered with bioactive molecules is explored. Control experiments and DFT calculations reveal that the reaction proceeds presumably via nucleophilic addition of the N2 (of the 1H tautomer) center to quinoid-carbene followed by a 1,5-H shift.

Leveraging Nonstrained C-C Bonds for Selective Carboacylation of an Unactivated Alkyne via Transient Dearomatization

Carboacylation of an unsaturated bond represents a powerful transformation. However, only a few examples of carboacylation of alkyne have been reported through C-C bond scission and reconnection. Here, we report a method of carboacylation of an unactivated alkyne by utilizing nonstrained C-C bonds under gold(I) catalysis. The density functional theory computational and experimental studies reveal that the reaction proceeds through a C-to-C formal 1,3-acyl migration via a solvent cage-nested acylium cation.

P(NMe2)3-Mediated Regioselective N-Alkylation of 2-Pyridones via Direct Deoxygenation of α-Keto Esters

A practical and regioselective direct N-alkylation of 2-pyridones is enabled by use of α-keto esters in the P(NMe2)3-mediated deoxygenation process. The reaction proceeds under mild conditions to produce N-alkylated 2-pyridones with high selectivity and generality, and the protocol is shown to be applicable for the scale-up synthesis, which makes it promising for practical applications.

Atroposelective Synthesis of N-N Axially Chiral Bipyrroles via Rhodium-Catalyzed C-H Insertion Reaction

An atroposelective synthesis of bipyrroles with an axially chiral N-N bond has been established via a rhodium-catalyzed C-H bond insertion reaction to provide the desired atropisomers in good yields (up to 97% yield) with good to excellent enantioselectivities (up to 99% ee).

Rh(II)-Catalyzed Synthesis of N-Aryl 2-pyridone Using 2-Oxypyridine and Diazonaphthoquinone Via 1,6-Benzoyl Migratory Rearrangement

A Rh(II)-catalyzed simple and efficient synthesis of N-arylated 2-pyridone derivatives is described using 2-oxypyridine and diazonaphthoquinone as coupling partners. The reaction proceeds through the insertion of the nitrogen atom of the 2-oxypyridine derivative into quinoid carbene and subsequent 1,6-benzoyl migratory rearrangement. The reaction is broadened with sufficient scope and has the potential to offer axially chiral N-arylated 2-pyridone derivatives under suitable asymmetric conditions.