RESUMO
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.
Assuntos
Ródio , Acrilatos , Alcinos , Catálise , CiclizaçãoRESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
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.
Assuntos
Compostos Policíclicos/síntese química , Compostos de Piridínio/síntese química , Ródio/química , Sais/síntese química , Catálise , Ligação de Hidrogênio , Cinética , Estrutura Molecular , Compostos Policíclicos/química , Compostos de Piridínio/química , Sais/químicaRESUMO
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 .
RESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
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.
Assuntos
Alcinos/química , Carbono/química , Hidrogênio/química , Hidroxiquinolinas/síntese química , Isoquinolinas/síntese química , Oximas/química , Ródio/química , Catálise , Ciclização , Hidroxiquinolinas/química , Isoquinolinas/química , Espectroscopia de Ressonância Magnética , Oxirredução , EstereoisomerismoAssuntos
Benzofenonas/química , Carbono/química , Cobre/química , Hidrogênio/química , Nitrogênio/química , Acridinas/química , Acridonas , Catálise , OxirreduçãoRESUMO
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.
RESUMO
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.
RESUMO
[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.