Rhodium(i)-catalyzed C6-selective C–H alkenylation and polyenylation of 2-pyridones with alkenyl and conjugated polyenyl carboxylic acids

Abstract

A versatile Rh(i)-catalyzed C6-selective decarbonylative C–H alkenylation of 2-pyridones with readily available alkenyl carboxylic acids has been developed.

Rh(III)‐catalyzed C6‐selective Acylmethylation and Carboxymethylation of 2‐Pyridones with Diazo Compounds

“…Given the general utility of this methodology, it would be very attractive to expand its application in the direct alkylation of other valuable aromatic N‐heterocycles. Continuing our interest in transition‐metal‐catalyzed C−H functionalization of 2‐pyridones [7o,8n] and other heteroarenes, [14] herein we report that, depending on the reaction conditions and diazo compounds, 1‐(2‐pyridyl)‐2‐pyridones could undergo Cp*Rh(III)‐catalyzed highly efficient C6‐selective deesterificative acylmethylation and deacetylative carboxymethylation, respectively, delivering the corresponding products in high yields with a wide substrate scope and good functional group tolerance (Scheme 1c).…”

Manganese(I)‐Catalyzed Site‐Selective C6‐Alkenylation of 2‐Pyridones Using Alkynes via C−H Activation

“…Recently, the group of Ackermann described the C6−H alkenylation of 1‐(2‐pyridyl)‐2‐pyridone with the terminal propargylic ester under synergistic catalysis of Brønsted acid and Mn(CO) 5 Br, but this reaction is reagent specific with only one example being given (Scheme 1a, path b) [5d] . More recently, the group of Hirano and Miura reported a Rh(III)‐catalyzed C6‐slective alkenylation of 1‐(2‐pyridyl)‐2‐pyridones with acrylates and styrenes (Scheme 1a, path c), [13b] and our group reported a Rh(I)‐catalyzed C6‐selective decarbonylative C−H alkenylation of 2‐pyridones with readily available, and inexpensive alkenyl carboxylic acids (Scheme 1a, path d) [13c] . However, their applications might be hampered by the high cost and scarcity of rhodium.…”

Recent Progress in Nitro-Promoted Direct Functionalization of Pyridones and Quinolones

“…Among the large number of aza-heterocycles available, pyridones and quinolones, both of which have a common six-membered aza-framework, exhibit a wide range of pharmacologically important activities ( Figure 1) [6][7][8][9][10]. Therefore, various methods for the preparation of structurally diverse pyridones and quinolones have been studied in detail [6,[11][12][13][14][15][16][17][18][19][20][21].…”

“…Among the large number of aza-heterocycles available, pyridones and quinolones, both of which have a common six-membered aza-framework, exhibit a wide range of pharmacologically important activities ( Figure 1) [6][7][8][9][10]. Therefore, various methods for the preparation of structurally diverse pyridones and quinolones have been studied in detail [6,[11][12][13][14][15][16][17][18][19][20][21]. Conventional strategies for the synthesis of aza-heterocycles involve (1) construction of azaheterocycle frameworks from prefunctionalized starting materials, (2) ring transformation leading to Conventional strategies for the synthesis of aza-heterocycles involve (1) construction of aza-heterocycle frameworks from prefunctionalized starting materials, (2) ring transformation leading to aza-heterocycle frameworks, and (3) direct functionalization of aza-heterocycle frameworks, which are supplementary to each other ( Figure 2) [22].…”

“…The nitro group is also a good leaving group, which is often involved in addition-elimination reactions [31,32]. To the best of our knowledge, the currently used methods for direct functionalization of the quinolone and pyridone scaffolds are mainly focused on transition-metal-catalyzed cross-coupling and C-H activation reactions [6,[11][12][13][14][15][16][17][18][19][20][21]. However, most of these methods suffer from some limitations, such as the use of potentially poisonous and expensive noble metals, along with harsh reaction conditions.…”