@article {46323, title = {Nickel-catalyzed C(2)-H arylation of indoles with aryl chlorides under neat conditions}, journal = {Journal of Organic Chemistry}, volume = {84}, year = {2019}, month = {OCT}, pages = {12800-12808}, type = {Article}, abstract = {

Nickel-catalyzed regioselective C(2)-H arylation of indoles and pyrroles with aryl chlorides is achieved under neat conditions. This method allows the efficient coupling of diverse aryl chlorides employing a user-friendly and inexpensive Ni(OAc)(2)/dppf catalyst system at 80 degrees C. Numerous functionalities, such as halides, alkyl ether, fluoro-alkyl ether, and thioether, and substituted amines, including heteroarenes like benzothiazolyl, pyrrolyl, indolyl, and carbazolyl, are well tolerated under the reaction conditions. The preliminary mechanistic study highlights a single-electron transfer (SET) pathway for the arylation reaction.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.9b01375}, author = {Pandey, Dilip K. and Vijaykumar, Muniyappa and Punji, Benudhar} } @article {47398, title = {Advances in transition-metal-catalyzed C-H bond oxygenation of amides}, journal = {Synthesis-Stuttgart}, year = {2021}, month = {APR }, type = {Article; Early Access}, abstract = {

C-O bond formation represents a fundamental chemical transformation in organic synthesis to develop valuably oxygenated (hetero)arenes. Particularly, the direct and regioselective C-H bond oxygenation of privileged amides, using a transition metal catalyst and a mild oxygenating source, is a step-economy and attractive approach. During the last decade, considerable progress has been realized in the direct C-H oxygenation of primary, secondary, and tertiary amides. This Short Review compiles the advances in transition-metal-catalyzed oxygenation of C(sp(2))-H and C(sp(3))-H bonds on various amides with diverse oxygenation sources. The review is categorized into two different major sections: (i) C(sp(2))-H oxygenation and (ii) C(sp(3))-H oxygenation. Each section is discussed based on the directing group (monodentate and bidentate) attached to the amide derivatives.

}, keywords = {Amides, C-H activation, directing group, Oxygenation, Transition Metal}, issn = {0039-7881}, doi = {10.1055/a-1481-2584, Early Access Date = APR 2021}, author = {Vijaykumar, Muniyappa and Punji, Benudhar} } @article {47607, title = {Pd(II)-catalyzed chemoselective acetoxylation of C(sp(2))-H and C(sp(3))-H bonds in tertiary amides}, journal = {Journal of Organic Chemistry}, volume = {86}, year = {2021}, month = {JUN }, pages = {8172-8181}, type = {Article}, abstract = {Palladium-catalyzed chemoselective C(sp(2))-H and C(sp(3))-H acetoxylation of synthetically useful tertiary amides is reported under relatively mild reaction conditions. This protocol proceeds through the assistance of a weakly coordinated directing group (C = O) and requires low catalyst (1.0 mol \%) loading. Diverse functionalities, such as C(sp(2))-Cl, C(sp(3))-Cl, -CF3, -COOEt, and -NO2 groups, including morpholinyl, piperazinyl, and pyrrolidinyl heterocycles, are compatible under the reaction conditions. Further functionalization of this protocol is demonstrated by hydrolysis to alcohols, alcohol-acids, as well as reduction to tertiary amines. A preliminary kinetic isotope effect study supported the rate-limiting C-H bond activation process.}, issn = {0022-3263}, doi = {10.1021/acs.joc.1c00629}, author = {Vijaykumar, Muniyappa and Punji, Benudhar} } @article {48270, title = {Palladium-catalyzed chemoselective oxygenation of C(sp2)-H and C(sp3)-H bonds in isatins}, journal = {Organic Letters}, volume = {25}, year = {2023}, month = {MAR}, pages = {1862-1867}, type = {Article}, abstract = {

The palladium-catalyzed chemoselective C(sp2)-H and C(sp3)-H bond oxygenation of substituted isatin derivatives is reported. This mild protocol exhibits the C5 C(sp2)-H oxygenation of isatins through electrophilic intermolecular C-H palladation in concentrated solutions using PhI(OAc)2 or Selectfluor as an oxidant, whereas it exhibits- N-CH3 C(sp3)-H oxygenation in dilute solutions via carbonyl-assisted intramolecular palladation in the presence of K2S2O8. This oxygenation reaction provides a direct and unified approach for synthesizing diverse oxygenated isatins with sensitive functionalities, including biorelevant compounds.

}, issn = {1523-7060}, doi = {10.1021/acs.orglett.3c00342}, author = {Vijaykumar, Muniyappa and Pradhan, Chandini and Gonnade, Rajesh G. and Punji, Benudhar} }