Kanniyappan Parthasarathy

Synthesis of Phenanthrone Derivatives from sec-Alkyl Aryl Ketones and Aryl Halides via a Palladium-Catalyzed Dual C−H Bond Activation and Enolate Cyclization

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.

Easy Access to Isoquinolines and Tetrahydroquinolines from Ketoximes and Alkynes via Rhodium-Catalyzed C−H Bond Activation

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.

Rhodium‐Catalyzed Oxidative Annulation of Sulfoximines and Alkynes as an Approach to 1,2‐Benzothiazines

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 .

Ru(II)-Catalyzed C–H Bond Activation for the Synthesis of Substituted Isoquinolinium Salts from Benzaldehydes, Amines, and Alkynes

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.

One-Pot Synthesis of Highly Substituted Polyheteroaromatic Compounds by Rhodium(III)-Catalyzed Multiple CH Activation and Annulation**

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.

Ru(II)-catalyzed amidation of 2-arylpyridines with isocyanates via C-H activation.

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

Rhodium(III)‐Catalyzed Selective ortho‐Olefinations of N‐Acyl and N‐Aroyl Sulfoximines by CH Bond Activation

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.

Direct Synthesis of Arylketones by Nickel-Catalyzed Addition of Arylboronic Acids to Nitriles

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.

Iron-Catalyzed Hetero-Cross-Dehydrogenative Coupling Reactions of Sulfoximines with Diarylmethanes: A New Route to N-Alkylated Sulfoximines

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.

Hydroarylations of Heterobicyclic Alkenes through Rhodium‐Catalyzed Directed CH Functionalizations of S‐Aryl Sulfoximines

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.