5782-24-1

Upstream product

• 95-20-5 2-methyl-1H-indole 
• 123-11-5 4-methoxy-benzaldehyde 
• 26211-90-5 2-methyl-3-(4-methoxybenzoyl)indole 
• 100-07-2 4-methoxy-benzoyl chloride 
• 105-13-5 4-Methoxybenzyl alcohol 
• 874-90-8 4-methoxybenzonitrile 
• 36634-78-3 (E)-2-methyl-3-styryl-1H-indole 
• 100-09-4 4-methoxybenzoic acid 

Downstream Products

• 1304141-49-8 (2R,3R)-3-(4-methoxybenzyl)-2-methylindoline 
• 1196824-76-6 C₂₆H₂₅NO₂ 
• 80749-38-8 2-acetamidophenyl 4-methoxyphenylmethyl ketone 

Relevant academic research and scientific papers

Cobalt-Catalyzed Hydrogenative Transformation of Nitriles

Here, we report the transformation of nitrile compounds in a hydrogen atmosphere. Catalyzed by a cobalt/tetraphosphine complex, hydrogenative coupling of unprotected indoles with nitriles proceeds smoothly in a basic medium, yielding C3 alkylated indoles. In addition, the direct hydrogenation of nitriles under the same conditions yielded primary amines. Isotope labeling experiments, along with a series of control experiments, revealed a reaction pathway that involves nucleophilic addition of indoles and 1,4-reduction of a conjugate imine intermediate. Different from reductive alkylation of indoles under an acidic condition, E1cB elimination is believed to occur in this base-promoted hydrogenative coupling reaction.

Bifunctional Iron Complexes Catalyzed Alkylation of Indoles

Cyclopentadienone iron carbonyl complexes have been applied in alkylation of indoles with various benzylic alcohols, aliphatic alcohols (butanol, ethanol, methanol and 2-methylpentanol) via the hydrogen autotransfer strategy in mild reaction conditions. Experimental works highlight the role of the bifunctional iron complexes and the base. These iron complexes demonstrated a broad applicability in mild conditions and extended the scope of substrates in iron catalyzed C?C bond formation. (Figure presented.).

Cobalt-catalysed reductive C-H alkylation of indoles using carboxylic acids and molecular hydrogen

The direct CH-alkylation of indoles using carboxylic acids is presented for the first time. The catalytic system based on the combination of Co(acac)3 and 1,1,1-tris(diphenylphosphinomethyl)-ethane (Triphos, L1), in the presence of Al(OTf)3 as co-catalyst, is able to perform the reductive alkylation of 2-methyl-1H-indole with a wide range of carboxylic acids. The utility of the protocol was further demonstrated through the C3 alkylation of several substituted indole derivatives using acetic, phenylacetic or diphenylacetic acids. In addition, a careful selection of the reaction conditions allowed to perform the selective C3 alkenylation of some indole derivatives. Moreover, the alkenylation of C2 position of 3-methyl-1H-indole was also possible. Control experiments indicate that the aldehyde, in situ formed from the carboxylic acid hydrogenation, plays a central role in the overall process. This new protocol enables the direct functionalization of indoles with readily available and stable carboxylic acids using a non-precious metal based catalyst and hydrogen as reductant.

Synthesis of bench-stable diarylmethylium tetrafluoroborates

A representative number of bench-stable nonsymmetric diarylcarbenium tetrafluoroborates have been isolated via the direct coupling of aryl (or heteroaryl) aldehydes and N-heteroarenes and fully characterized. They have proven to be highly stable in the pr

Homogenous Pd-catalyzed asymmetric hydrogenation of unprotected indoles: Scope and mechanistic studies

An efficient palladium-catalyzed asymmetric hydrogenation of a variety of unprotected indoles has been developed that gives up to 98% ee using a strong Br?nsted acid as the activator. This methodology was applied in the facile synthesis of biologically active products containing a chiral indoline skeleton. The mechanism of Pd-catalyzed asymmetric hydrogenation was investigated as well. Isotope-labeling reactions and ESI-HRMS proved that an iminium salt formed by protonation of the C=C bond of indoles was the significant intermediate in this reaction. The important proposed active catalytic Pd-H species was observed with 1H NMR spectroscopy. It was found that proton exchange between the Pd-H active species and solvent trifluoroethanol (TFE) did not occur, although this proton exchange had been previously observed between metal hydrides and alcoholic solvents. Density functional theory calculations were also carried out to give further insight into the mechanism of Pd-catalyzed asymmetric hydrogenation of indoles. This combination of experimental and theoretical studies suggests that Pd-catalyzed hydrogenation goes through a stepwise outer-sphere and ionic hydrogenation mechanism. The activation of hydrogen gas is a heterolytic process assisted by trifluoroacetate of Pd complex via a six-membered-ring transition state. The reaction proceeds well in polar solvent TFE owing to its ability to stabilize the ionic intermediates in the Pd-H generation step. The strong Br?nsted acid activator can remarkably decrease the energy barrier for both Pd-H generation and hydrogenation. The high enantioselectivity arises from a hydrogen-bonding interaction between N-H of the iminium salt and oxygen of the coordinated trifluoroacetate in the eight-membered-ring transition state for hydride transfer, while the active chiral Pd complex is a typical bifunctional catalyst, effecting both the hydrogenation and hydrogen-bonding interaction between the iminium salt and the coordinated trifluoroacetate of Pd complex. Notably, the Pd-catalyzed asymmetric hydrogenation is relatively tolerant to oxygen, acid, and water.

Preparation and characterization of aryl or heteroaryl(3-indolyl)methylium o-benzenedisulfonimides

An initial study has been accomplished into the synthetic feasibility of the preparation of diarylcarbenium salt via the direct coupling of aryl (or heteroaryl) aldehydes and arenes (or heteroaryl analogues) in the presence of a strong organic Bronsted acid. A number of stabilized aryl or heteroaryl(3-indolyl)carbenium ions, never previously prepared in the solid state, have been isolated in excellent yields as highly stable o-benzenedisulfonimide salts and have been fully characterized. Their purity has been proven by spectroscopic methods and chemical reduction with NaBH 4. An X-ray crystal structure analysis has been performed on one of the products: an azafulvenium species was shown to be the exclusive structure in the solid state.

An efficient route to 2,3-disubstituted indoles via reductive alkylation using H2 as reductant

An efficient route to 2,3-disubstituted indoles was developed via reductive alkylation of 2-substituted indoles using hydrogen as a clean and atom economic reductant under ambient pressure.

Catalytic stereoselective benzylic C-H functionalizations by oxidative C-H activation and organocatalysis

An organocatalytic stereoselective α-alkylation reaction of aldehydes based on C-H activation is presented.

A Mild and Selective C-3 Reductive Alkylation of Indoles

In the presence of triethylsilane and trifluoroacetic acid, the reaction between indoles and aldehydes in dichloromethane at 0 deg C, results in good yields of C-3 reductively alkylated products.The transformation is most effective for the preparation of 3-(arylmethyl)indoles 6 from aromatic aldehydes.