Transition-metal-catalyzed cyclization of substituted aromatics with carbon−carbon π-components via C−H bond activation is a promising method to construct carbocyclic and heterocyclic molecules in a highly atom- and step-economical manner.1 With our continuous interest in transition-metal-catalyzed cyclization reactions, we have investigated the reaction of substituted N-methoxy benzamides or N-chloro benzamides with maleimides or 1,3-dienes in the presence of a metal catalyst under the redox neutral version. N-Methoxy benzamides react with maliemides in presence of a Rh(III) catalyst to afford spiroindolinone moieties in moderate to good yields.2a On the other hand, N-chloro benzamides reacted with 1,3-dienes in presence of a Co(III) catalyst providing pharmaceutically important 3,4-dihydroisoquinolinone derivatives in good yields.2b The reaction of N-chloro benzamides with alkylidenecyclopropanes in presence of a Co(III) catalyst furnished 3,4-dihydroisoquinolinone derivatives in good to excellent yields.2c Benzoic acids react with alkylidenecyclopropanes in presence of a Ru(II) catalyst provided (E)-4-benzylideneisochroman-1-ones.2d Further, we have disclosed a ruthenium-catalyzed remote C−H sulfonylation at the C5 position of the pyridyl group of N-aryl-2-aminopyridines with aromatic sulfonyl chlorides via the C−H bond activation.2e

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[1] (a) Arockiam, P. B.; Bruneau, C.; Dixneuf, P. H. Chem. Rev. 2012, 112, 5879. (b) Leitch, J. A.; Frost, C. G. Chem. Soc. Rev. 2017, 46, 7145. (c) Manikandan, R.; Madasamy, P.; Jeganmohan, M. ACS Catal. 2016, 6, 230.
[2] (a) Ramesh, B.; Tamizmani, M.; Jeganmohan. M. J. Org. Chem. 2019, 84, 4058. (b) Ramesh, B.; Jeganmohan. M. manuscript under reviewing. (c) Ramesh, B.; Jeganmohan. M. Chem. Commun. 2021, 57, 3692. (d) Ramesh, B.; Jeganmohan. M. J. Org. Chem. 2022, under minor revision. (e) Ramesh, B.; Jeganmohan. M. Org. Lett. 2017, 19, 6000.