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A simple and efficient Ru(II)-catalyzed olefination of 3-(arylbenzylidene)indolin-2-ones with alkenes is described. This is an atom and step-economical strategy with a wide substrate scope, good functional group tolerance, and suitability for gram scale synthesis. A plausible mechanism is also proposed for this synthetic transformation involving the formation of a 5-membered ruthenacycle and insertion of the alkene followed by β-hydride elimination to deliver the desired product.

A new palladium-catalyzed efficient method for the synthesis of substituted 9,10-phenanthrenes from 2-biaryl triflates with alkynes has been developed. This method provides a great opportunity to prepare various symmetrical and unsymmetrical phenanthrene derivatives in good yields. This reaction proceeds via C-OTf bond cleavage and alkyne insertion followed by C-H annulation.

A new and efficient protocol has been demonstrated for the synthesis of benzothiadiazinoisoquinoline 6,6-dioxides and benzothiadiazinoisoindole 5,5-dioxides in good to excellent yields. These compounds are formed through a sequential Rh(III)-catalyzed C-H cyclization of dihydrophenylbenzothiadiazine 1,1-dioxides with alkynes and oxidative Heck coupling/aza-Michael addition of dihydrophenylbenzothiadiazine 1,1-dioxides with acrylates, respectively.

The Ni(II)-catalyzed aromatic homologation of various directing groups with alkynes to afford highly substituted naphthalene products via C-X bond cleavage followed by alkyne insertion and C-H activation is described. This reaction proceeded with a wide range of directing groups such as pyrazoles, imidazopyridines, benzoimidazothiazoles, thiazoles and triazoles with alkynes to afford highly substituted naphthalenes in moderate to good yields. This transformation is promoted by a simple, straightforward combination of a Ni(II)-complex, Zn dust and a base.

An efficient Rh(III)-catalyzed cross-dehydrogenative coupling of N -pyridinylindoles with benzo[ b ]thiophene 1,1-dioxides has been developed through directing-group-assisted C-H activation. This transformation constructs a new C-C bond from two inert C-H bonds in a one-pot reaction. The present reaction is compatible with various functional groups with respect to indoles and benzothiophene[ b ] 1,1-dioxides. Furthermore, the emission properties of synthesized compounds have been explored.

The catalyst-free 1,6-conjugate addition of indoles and 4-hydroxycoumarins to para-quinone methides is reported. This protocol allowed us to access a range of unsymmetrical triarylmethanes in good to excellent yields. The outlined procedure is operationally simple, efficient, atom and step economical. The synthesized heterocyclic triarylmethanes were further converted into highly substituted indoloisoquinolines and pyranochromenones via metal-catalyzed C-H activation/annulation.

An inexpensive and benchtop stable Ni-catalyst/Zn system for the synthesis of pyrrolo/indoloquinolines and indolo[2,1- a ]isoquinolines is explored. This platform provides a one-pot entry for the preparation of various pyrrolo and indoloquinolines/isoquinolines, which involves successive C-C and C-N bond formation, respectively. In addition, we have also performed the preliminary photophysical studies for the synthesized compounds.

Rhodium(III)-catalyzed ortho brominations and iodinations of N-acylsulfoximines by C-H bond activations have been developed. Subsequent product functionalizations involving cross-coupling reactions provide alkynylated sulfoximine derivatives and benzothiazines with wide potential for further synthetic applications.

Rhodium-catalyzed directed CH-functionalizations have been used in hydroarylations of heterobicyclic alkenes with NH-sulfoximines. Unexpectedly, the bicyclic framework is retained, resulting in the formation of addition products being attractive intermediates for functionalized molecules that are difficult to prepare by other means., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new method for the synthesis of highly substituted naphthyridine-based polyheteroaromatic compounds in high yields proceeds through rhodium(III)-catalyzed multiple C-H bond cleavage and C-C and C-N bond formation in a one-pot process. Such highly substituted polyheteroaromatic compounds have attracted much attention because of their unique π-conjugation, which make them suitable materials for organic semiconductors and luminescent materials. Furthermore, a possible mechanism, which involves multiple chelation-assisted ortho C-H activation, alkyne insertion, and reductive elimination, is proposed for this transformation., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Rhodium-catalyzed C-H functionalizations have been used for ortho-directed additions of 2-arylpyridines and (hetero)aryl-substituted pyrimidines, isoquinolines, and benzo[h]quinolones to cyclic imines. The resulting amino-functionalized products are formed in good to high yields.

Two new rhodium-catalyzed oxidative couplings between sulfoximine derivatives and alkenes by regioselective CH activation, affording ortho-olefinated (Heck-type) products, are reported. A synthetic application of the ortho-alkenylated products into the corresponding cyclic derivatives has been demonstrated, and a mechanistic rational for the rhodium catalysis is presented., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient iron-catalyzed C-N bond formation by hetero-cross-dehydrogenative coupling (CDC) between sulfoximines and diarylmethanes is described. The reaction shows good functional group tolerance and provides N-alkylated sulfoximines in moderate to good yields.

Revitalization by oxygen: A rhodium(III)-catalyzed oxidative CH/NH activation/annulation sequence provided access to a variety of substituted 1,2-benzothiazine derivatives from readily available NH-sulfoximines and alkynes (see scheme; Cp*=C5 Me5 ). The oxidation system consisted of molecular oxygen in combination with a catalytic amount of Fe(OAc)2 ., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient and convenient method for the synthesis of highly substituted polycyclic pyridinium salts from the reaction of various 2-aryl-pyridines and 2-aryl-sp(2) -nitrogen-atom-containing heterocycles with alkynes through rhodium(III)-catalyzed CH activation and annulation under an O2 atmosphere is described. A possible mechanism that involves the chelation-assisted CH activation of the 2-aryl-pyridine substrate, insertion of the alkyne, and reductive elimination is proposed. This mechanism was supported by the isolation of a five-membered rhodacycle (I'). In addition, kinetic isotope studies were performed to understand the intimate reaction mechanism., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient method for the one-pot synthesis of substituted phenanthridinone derivatives from N-methoxybenzamides and aryltriethoxysilanes through rhodium-catalyzed dual C-H bond activation and annulation reactions is described. A double-cycle mechanism is proposed to account for this catalytic reaction. In addition, isotope-labeling studies were performed to understand the intimate mechanism of the reaction., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient Ru(II)-catalyzed amidation of 2-arylpyridines with isocyanates via C-H bond activation is described.

An efficient method for the synthesis of substituted isoquinolinium salts from benzaldehydes, amines, and alkynes via ruthenium-catalyzed C-H bond activation and annulation in one pot is described.

A new method for the synthesis of various isochromen-6-ones and phenanthro[1,10-bc]oxepines via a palladium-catalyzed cascade carbocyclization of 2-iodobenzyl-3-phenylpropiolates and 1-iodo-2-(2-(phenylethynyl)benzyloxy)benzenes with arynes is described. The reactions involve interesting biscarbocyclization of alkynes and benzynes and C-H bond activation.

A convenient method for the synthesis of highly substituted isoquinolines and isoquinolinium salts by the nickel-catalyzed cyclization of ortho-haloketoximes and -ketimines, respectively, with alkynes is described. The reaction of ortho-haloketoximes and various alkynes in the presence of [Ni(PPh(3))(2)Br(2)] and zinc powder in a mixture of acetonitrile and tetrahydrofuran at 80 °C for 15 hours gave 1,3,4-trisubstituted isoquinoline products in moderate to excellent yields and high regioselectivity. The corresponding isoquinoline N-oxide was found to be the intermediate in the cyclization reaction pathway. In contrast, the reaction of ortho-haloketimines and alkynes under similar catalytic conditions in tetrahydrofuran at 70 °C for two hours gave 1,2,3,4-tetrasubstituted isoquinolinium salts in good to excellent yields., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A cobalt-catalyzed addition of aryl- and alkenylboronic acids to aldehydes and phthalaldehyde to give the corresponding biarylketones and 3-aryl phthalides in good to excellent yields in one pot is described., (This journal is © The Royal Society of Chemistry 2011)

A highly regio- and stereoselective nickel-catalyzed three-component coupling of alkynes with enones and alkenyl boronic acids to afford highly substituted 1,3-dienes is described. The reaction can also be extended to cyclization of enynes with coupling to alkenyl boronic acids. A possible reaction mechanism involving a five-membered nickelacycle as a key intermediate is proposed.

An efficient method for the synthesis of substituted 1(2H)-isoquinolone derivatives via nickel-catalyzed annulation of substituted 2-halobenzamides with alkynes is described. This protocol is successfully applied to the total synthesis of oxyavicine with excellent yield.

A palladium-catalyzed chelation-assisted C-H activation of alkyl aryl ketones and their reaction with aryl iodides to afford ortho-arylated products is described. For sec-alkyl aryl ketones, the catalytic reaction proceeds further to give 10,10-dialkylphenanthrone derivatives. A possible reaction mechanism involving directed dual C-H bond activation and enolate cyclization for the formation of 10,10-dialkylphenanthrone derivatives is proposed.

A convenient and efficient method for the synthesis of various arylketones by nickel-catalyzed addition of arylboronic acids to nitriles is described. A catalytic cycle involving Ni(II) species as the catalytic intermediates is proposed to account for the present catalytic reaction.

A convenient and highly regioselective method for the synthesis of 5-methylenepyrrolidinone derivatives from various nitriles and acrylamides via a cobalt-catalyzed reductive coupling reaction is described. A possible mechanism that involves the formation of a cobaltaazacyclopentene intermediate from nitrile and acrylamide, protonation, keto-amide cyclization, and dehydration is proposed.

Described herein is a convenient and highly regioselective synthesis of substituted isoquinoline derivatives from various aromatic ketoximes and alkynes via a one-pot, rhodium-catalyzed C-H bond activation. In addition, tetrahydroquinoline derivatives are formed in good yields from 2-arylidene-1-cyclohexanone oximes possessing an exocyclic double bond and from tetrahydroxanthone oximes. A possible mechanism is proposed that involves chelation-assisted C-H activation via oxidative addition of Rh(I) to an ortho-C-H bond, insertion of the alkyne, reductive elimination, intramolecular electrocyclization, and aromatization. This mechanism is supported by isolation of the ortho-alkenylation products 7p and 7q. Also described herein is an example of an iridium-catalyzed activation of an sp(3) C-H bond.

A rhodium-catalyzed chelation-assisted C-H activation of alpha,beta-unsaturated ketoximes and the reaction with alkynes to afford highly substituted pyridine derivatives is described.

[reaction: see text] An efficient ring closure of 2-iodophenoxy-, 2-iodobenzyloxy-, and 2-iodobenzylaminoallenes followed by ring opening of oxabenzonorbornadienes leading to the synthesis of 2-benzofuranyl, 1H-isochromenyl, or 1,2-dihydroisoquinoline methyl-1,2-dihydro-1-naphthalenol derivatives catalyzed by palladium complexes is described.