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A transition metal-catalyzed carbene insertion strategy has been developed to activate the inactivated sp2 C–H bond of medicinally important cis-stilbene acids. This approach enables the facile construction of α-pyrone and chromene-2-one skeletons on the olefinic bond of cis-stilbene acid with high atom economy, good yield, broad functional group tolerance and gram-scale synthetic feasibility. The strategy unveils the efficiency of acid functionalities as directing groups along with sulfoxonium and hypervalent iodonium ylide as carbene precursors. The constructed architectures were explored for their photophysical properties showing emission ranging from 500 to 600 nm, and the biological potential was examined through molecular docking analysis and percentage inhibition studies. Additionally, ESI-MS studies were also performed to identify the key intermediates, helping to sketch a probable mechanism. [ABSTRACT FROM AUTHOR]

A facile, metal- and additive-free C–C bond construction between imidazo[1,2-a]pyridines and coumarin-3-carboxylic acids through a decarboxylative Michael addition is reported to achieve an imidazo[1,2-a]pyridin-3-yl-chroman-2-one skeleton. In addition, heterocyclic polyaromatic dibenzoisochromenoimidazo[1,2-a]pyridin-6-ones of value for future medicinal chemistry can be obtained successfully by this procedure through a domino reaction involving Michael addition/decarboxylation/oxidation/C–H bond activation and annulation. [ABSTRACT FROM AUTHOR]

Retraction of 'Ruthenium(II) CNN Pincer Complexes as Efficient Catalysts in Oxidative Annulation of Aromatic Acids with Alkynes to Isocoumarins' by Periasamy Viswanathamurthi et al., New J. Chem., 2023, https://doi.org/10.1039/D3NJ03745B. [ABSTRACT FROM AUTHOR]

The acetic acid promoted reaction of 3-hydroxy-3-(indol-3-yl)indolin-2-ones and mercapto-substituted β-enamino esters showed very interesting molecular diversity. The reaction in ethanol at room temperature in the presence of acetic acid resulted in two diastereoisomeric 3,3-disubstituted oxindoles in high yields. When the reaction was carried out in refluxing ethanol, the reaction with 3-hydroxy-3-(indol-3-yl)indolin-2-ones with N-alkyl groups gave polycyclic spirooxindoles in satisfactory yields. However, a similar reaction with 3-hydroxy-3-(indol-3-yl)indolin-2-ones with NH groups afforded functionalized dihydroindolo[3,2-c]phenothiazines with sequential ring-opening of oxindole. A plausible domino annulation mechanism was rationally proposed for the formation of different kinds of polycyclic compounds. [ABSTRACT FROM AUTHOR]

Herein, we report the rhodium-catalyzed domino arylation/cyclization reaction of unactivated internal alkynes to afford the optically active indenols in excellent yields (up to 92%) and extremely high enantioselectivities (up to 99% ee) in the presence of new amide substituted chiral diene ligands. Notably, a total of 21 new chiral diene ligands are synthesized, which are potential choices for other asymmetric reactions. [ABSTRACT FROM AUTHOR]

A new electrochemical decarboxylative [4+2] annulation of arylglyoxylic acids with internal alkynes involving C–H functionalization by means of a cooperative anode and ruthenium catalysis is presented. This reaction represents a mechanistically novel strategy as an ideal supplement to the decarboxylative [4+2] annulation methodology by employing an electrooxidative process to avoid the use of an additional external oxidizing reagent and utilizing H2O as the carboxyl oxygen atom source to be engaged in the synthesis of 1H-isochromen-1-ones. [ABSTRACT FROM AUTHOR]