Selective Ruthenium-Catalyzed Three-Component Synthesis of Pyrroles

Iridium Catalyzed Synthesis of Tetrahydro-1H-Indoles by Dehydrogenative Condensation

Novel synthetic routes to the commonly encountered indole motif are highly sought after. Tetrahydro-1H-indoles were synthesized for the first time from secondary alcohols and 2aminocyclohexanol in the presence of a well-established iridium catalyst using a modified synthetic procedure recently developed for the synthesis of hydrocarbazoles. The catalyst is stabilized by an inexpensive and easy-to-synthesize triazine based PN5P pincer ligand. The reaction proceeds through acceptorless dehydrogenative condensation (ADC) and yields the title compound, dihydrogen, and water and can thus be classified as sustainable synthesis. Overall, five examples, three of which were previously unknown compounds, were prepared. The propitious isolated yields and the mild reaction conditions show the synthetic value of this approach. These tetrahydroindoles can be quantitatively dehydrogenated over a heterogeneous Pd catalyst to yield the corresponding indoles.

Manganese-Catalyzed Multicomponent Synthesis of Pyrroles through Acceptorless Dehydrogenation Hydrogen Autotransfer Catalysis: Experiment and Computation

A new base metal catalyzed sustainable multicomponent synthesis of pyrroles from readily available substrates is reported. The developed protocol utilizes an air- and moisture-stable catalyst system and enables the replacement of themutagenic α-haloketones with readily abundant 1,2-diols. Moreover, the presented method is catalytic in base and the sole byproducts of this transformation are water and hydrogen gas. Experimental and computational mechanistic studies indicate that the reaction takes place through a combined acceptorless dehydrogenation hydrogen autotransfer methodology.

Thienylbenzotriazole promoted highly active gold nanoparticles supported on N-doped graphene as efficient catalysts in water and a mechanism exploration

Gold nanocomposite catalyzed alkylation of ketone with alcohol, alcohol and alcohol, particularly for amine and amine in water.

Cooperative ruthenium complex catalyzed multicomponent synthesis of pyrimidines

The ruthenium-catalyzed multicomponent synthesis of pyrimidines from amidines and alcohols is reported for the first time.

Immobilization of manganese dioxide nanoparticles on modified poly 2,4-dichlorostyrene microspheres: a highly efficient and recyclable catalyst for borrowing hydrogen reactions

Modified poly 2,4-dichlorostyrene microspheres were designed and synthesized, and were proved to be an effective carrier to synthesize supported manganese dioxide nanoparticles.

Acceptorless Dehydrogenative Coupling Using Ammonia: Direct Synthesis of N-Heteroaromatics from Diols Catalyzed by Ruthenium

The synthesis of N-heteroaromatic compounds via an acceptorless dehydrogenative coupling process involving direct use of ammonia as the nitrogen source was explored. We report the synthesis of pyrazine derivatives from 1,2-diols and the synthesis of N-substituted pyrroles by a multicomponent dehydrogenative coupling of 1,4-diols and primary alcohols with ammonia. The acridine-based Ru-pincer complex 1 is an effective catalyst for these transformations, in which the acridine backbone is converted to an anionic dearomatized PNP-pincer ligand framework.

Synthesis of Pyrazines and Quinoxalines via Acceptorless Dehydrogenative Coupling Routes Catalyzed by Manganese Pincer Complexes

Base-metal catalyzed dehydrogenative self-coupling of 2-amino alcohols to selectively form functionalized 2,5-substituted pyrazine derivatives is presented. Also, 2-substituted quinoxaline derivatives are synthesized by dehydrogenative coupling of 1,2-diaminobenzene and 1,2-diols. In both cases, water and hydrogen gas are formed as the sole byproducts. The reactions are catalyzed by acridine-based pincer complexes of earth-abundant manganese.

Direct Biomimetic Synthesis of β-Carboline Alkaloids from Two Amino Acids

The increasing importance of enzyme mimics in organic synthesis inspired us to design a novel biomimetic synthesis of β-carboline alkaloids directly from tryptophan and a second amino acid. This novel one-pot protocol utilizes abundant and readily available starting materials and thus presents a green and user-friendly alternative to conventional methods that rely on stepwise synthesis. Driven by molecular iodine and TFA, decarboxylation, deamination, Pictet-Spengler reaction, and oxidation reactions proceeded sequentially, transforming biomass amino acids into value-added alkaloid motifs.

Cobalt-catalyzed acceptorless dehydrogenative coupling of aminoalcohols with alcohols: direct access to pyrrole, pyridine and pyrazine derivatives

A molecularly defined SNS-cobalt(ii) catalyst for the acceptorless dehydrogenative coupling (ADC) of unprotected amino alcohols with secondary alcohols leading to pyrrole and pyridine derivatives is reported.

Preparation of pyridyltriazole ruthenium complexes as effective catalysts for the selective alkylation and one-pot C–H hydroxylation of 2-oxindole with alcohols and mechanism exploration

Pyridyltriazole-ligated ruthenium(ii) complexes have been designed and synthesized, which were characterized by X-ray crystallography.

Phosphine free Mn-complex catalysed dehydrogenative C–C and C–heteroatom bond formation: a sustainable approach to synthesize quinoxaline, pyrazine, benzothiazole and quinoline derivatives

Sustainable synthesis of quinoxalines, pyrazines, benzothiazoles and quinolines catalysed by a phosphine free Mn(i) complex.

Microwave-Assisted Regioselective Synthesis of 3-Functionalized Indole Derivatives via Three-Component Domino Reaction

A microwave-assisted regioselective synthesis of 3-functionalized indole derivatives via a three-component domino reaction of anilines, arylglyoxal monohydrates, and cyclic 1,3-dicarbonyl compounds is described. The main advantages of this protocol are short reaction times, practical simplicity, its metal-free nature, the availability of starting materials, green solvents, and high regioselectivity.

Hydrogen autotransfer and related dehydrogenative coupling reactions using a rhenium(i) pincer catalyst

A novel rhenium complex bearing a non-innocent PNP pincer ligand was prepared.