01258nas a2200169 4500008004100000022001400041245009100055210006900146260000800215300001600223490000700239520065800246100002200904700002600926700002000952856011600972 2019 eng d a0022-326300aNickel-catalyzed C(2)-H arylation of indoles with aryl chlorides under neat conditions0 aNickelcatalyzed C2H arylation of indoles with aryl chlorides und cOCT a12800-128080 v843 a

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.

1 aPandey, Dilip, K.1 aVijaykumar, Muniyappa1 aPunji, Benudhar uhttps://library.ncl.res.in/content/nickel-catalyzed-c2-h-arylation-indoles-aryl-chlorides-under-neat-conditions01525nas a2200193 4500008004100000022001400041245007400055210006900129260000900198520088800207653001101095653001901106653002001125653001601145653002101161100002601182700002001208856010301228 2021 eng d a0039-788100aAdvances in transition-metal-catalyzed C-H bond oxygenation of amides0 aAdvances in transitionmetalcatalyzed CH bond oxygenation of amid cAPR 3 a

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.

10aAmides10aC-H activation10adirecting group10aOxygenation10aTransition Metal1 aVijaykumar, Muniyappa1 aPunji, Benudhar uhttps://library.ncl.res.in/content/advances-transition-metal-catalyzed-c-h-bond-oxygenation-amides01345nas a2200157 4500008004100000022001400041245010400055210006900159260000900228300001400237490000700251520076000258100002601018700002001044856012301064 2021 eng d a0022-326300aPd(II)-catalyzed chemoselective acetoxylation of C(sp(2))-H and C(sp(3))-H bonds in tertiary amides0 aPdIIcatalyzed chemoselective acetoxylation of Csp2H and Csp3H bo cJUN  a8172-81810 v863 aPalladium-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.1 aVijaykumar, Muniyappa1 aPunji, Benudhar uhttps://library.ncl.res.in/content/pdii-catalyzed-chemoselective-acetoxylation-csp2-h-and-csp3-h-bonds-tertiary-amides01289nas a2200181 4500008004100000022001400041245009300055210006900148260000800217300001400225490000700239520065100246100002600897700002200923700002400945700002000969856011800989 2023 eng d a1523-706000aPalladium-catalyzed chemoselective oxygenation of C(sp2)-H and C(sp3)-H bonds in isatins0 aPalladiumcatalyzed chemoselective oxygenation of Csp2H and Csp3H cMAR a1862-18670 v253 a

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.

1 aVijaykumar, Muniyappa1 aPradhan, Chandini1 aGonnade, Rajesh, G.1 aPunji, Benudhar uhttps://library.ncl.res.in/content/palladium-catalyzed-chemoselective-oxygenation-csp2-h-and-csp3-h-bonds-isatins01350nas a2200181 4500008004100000022001400041245011500055210006900170260000900239300001600248490000700264520067400271100002600945700002200971700002400993700002001017856013101037 2024 eng d a1359-734500aChelation-assisted and steric-controlled selectivity in the Pd-catalyzed C-H/C-H oxidative coupling of indoles0 aChelationassisted and stericcontrolled selectivity in the Pdcata cNOV  a13028-130310 v603 a

We report the first regioselective C2-C7 oxidative coupling of indoles using a palladium catalyst upon the strategic installation of N-pyridinyl and C3-carbonyl, which delivers 2,7-biindoles with a broad scope (25 examples; up to 93% yield). Isolation of the catalytic intermediate reveals the initial activation of the C(7)-H bond, followed by the C(2)-H bond in indoles, and the reaction proceeds via a Pd(ii)/Pd(0) pathway. This manuscript describes the first regioselective C2-C7 oxidative coupling of indoles using a palladium catalyst through the strategic installation of N-pyridinyl and C3-carbonyl, which delivers diverse biorelevant 2-7-biindoles.

1 aVijaykumar, Muniyappa1 aPradhan, Chandini1 aGonnade, Rajesh, G.1 aPunji, Benudhar uhttps://library.ncl.res.in/content/chelation-assisted-and-steric-controlled-selectivity-pd-catalyzed-c-hc-h-oxidative-coupling02021nas a2200217 4500008004100000022001400041245011000055210006900165260000800234490000700242520126500249653001901514653001201533653001401545653001901559653002601578100002601604700002401630700002001654856012901674 2025 eng d a1867-388000aPalladium-catalyzed regioselective C(4)-H fluoroalkoxylation of indoles through weak chelation assistance0 aPalladiumcatalyzed regioselective C4H fluoroalkoxylation of indo cJAN0 v173 a

Installing fluoroalkyl motifs into biorelevant indoles is particularly interesting due to their ubiquitous presence in drug molecules. Herein, we demonstrate the regioselective C4 fluoroalkoxylation of indoles using fluoroalcohols via palladium-catalyzed chelation-assisted C & horbar;H activation. The weak chelating benzoyl moiety at the C3 position acts as a directing group for remote C(4)& horbar;H fluoroalkoxylation of diversely substituted indoles. This methodology demonstrates a high level of regioselectivity and tolerates a range of crucial functional groups, yielding diverse trifluoroalkoxylated indoles in moderate to good yields. Removal of directing/protecting groups and further functionalization established the synthetic utility of the methodology. A preliminary mechanistic investigation is conducted by isolating the palladacycle intermediate and performing the deuterium scrambling study. The regioselective C4 fluoroalkoxylation of indoles with various fluoroalcohols is achieved by the palladium-catalyzed weak chelation assistance strategy. The reaction is compatible for a range of important functionalities and proceeds via the intermediacy of a six-membered palladacycle following a Pd(II)/Pd(IV) pathway. image

10aC-H activation10aindoles10aPalladium10aRegioselective10aTrifluoroalkoxylation1 aVijaykumar, Muniyappa1 aGonnade, Rajesh, G.1 aPunji, Benudhar uhttps://library.ncl.res.in/content/palladium-catalyzed-regioselective-c4-h-fluoroalkoxylation-indoles-through-weak-chelation