Construction of 2-pyridones via oxidative cyclization of enamides: access to Pechmann dye derivatives

Abstract

An efficient protocol for the construction of structurally diverse 2-pyridone derivatives from imines and α,β-unsaturated acid chlorides in a single operation is reported.

A Ru(ii)-catalyzed C–H activation and annulation cascade for the construction of highly coumarin-fused benzo[a]quinolizin-4-ones and pyridin-2-ones

“…To further improve the effect of additives, we changed the number of equivalents of the additive from 2 to 0.5 in one test and to 3 in another (Table 1, entries 11 and 12), but both tests showed reduced yields of 3aa. In a screening of silver salts, AgSbF 6 provided the highest yield and the removal of silver salts resulted in no target product (Table 1, entries [13][14][15][16]. Subsequently, we kept the optimal catalytic system to investigate reaction solvents.…”

“…14 Similarly, dihydroisoquinoline with classic cycloaddition strategies was used to build polycyclic coumarin-derived 8-oxoprotoberbines. 15 The substrates for these constructions were relatively complex and needed to be prepared using multiple reaction steps. It has so far been rare and difficult to build highly coumarin-fused derivatives by using simple starting materials via a one-pot multi-step reaction strategy involving C-H activation and cyclization cascade steps.…”

Mechanistic insight into Cp*Rh(iii)-catalyzed Lossen rearrangement vs C–N reductive elimination for the synthesis of pyridones

“…Pyridones are a unique class of heterocyclic compounds that have been utilized as important scaffolds in drug discovery due to their relevant biological activities. 1,2 The introduction of fluorine or fluorine-containing motifs serves to improve the physicochemical properties of bioactive pyridines. 3,4 A powerful strategy for the synthesis of pyridones via transition metalcatalyzed C-H annulations of benzamides with fluoroalkynes has been reported.…”