Reductive Alkylation Of Indoles Research Articles

Molecular Iodine‐Catalysed Reductive Alkylation of Indoles: Late‐Stage Diversification for Bioactive Molecules

AbstractHerein, we report a molecular iodine‐catalysed reductive alkylation of indoles with carbonyl compounds using Et3SiH for the efficient synthesis of C3‐alkylated indoles. This metal‐free and environmental‐friendly process exhibits excellent functional group tolerance, mild conditions, and wide substrate scope. Notably, the synthetic usefulness of this strategy to pharmacochemistry was highlighted by the late‐stage modification of drug‐like molecules.

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.

Directly Bridging Indoles to 3,3'-Bisindolylmethanes by Using Carboxylic Acids and Hydrosilanes under Mild Conditions.

A straightforward Lewis acid-promoted protocol for 3,3'-bisindolylmethanes (BIMs) synthesis by reductive alkylation of indoles at the C3 position with carboxylic acids in the presence of hydrosilane was developed for the first time. Instead of aldehydes, more readily available, stable, and easy-to-handle carboxylic acids have been employed as alternative alkylating agents. As an efficient organocatalyst, B(C6 F5 )3 enables the reductive alkylation of various substituted indole derivatives with carboxylic acids with up to 98 % yield at room temperature and under neat conditions. This metal-free strategy offers an alternative approach for the direct functionalization of indoles to BIMs with carboxylic acids and such protocol allows selective reduction of carboxylic acid to aldehyde in combination with C-C bond formation.

ChemInform Abstract: Easy Access to a Library of Alkylindoles: Reductive Alkylation of Indoles with Carbonyl Compounds and Hydrosilanes under Indium Catalysis.

AbstractVarious functionalized indoles are alkylated with a diverse range of alkyl, aryl or hetaryl aldehydes or ketones following a practical and scalable one or two step procedure.

Easy Access to a Library of Alkylindoles: Reductive Alkylation of Indoles with Carbonyl Compounds and Hydrosilanes under Indium Catalysis

AbstractBy applying carbonyl compounds as sources of alkyl groups to the indium‐catalyzed reductive alkylation of indoles, a reliable and practical method capable of offering a wide range of alkylindoles with structural diversity has been developed. An important feature of this method is that the loading of the indium catalyst can be reduced by more than that of the original alkyne‐based system.magnified image

ChemInform Abstract: Synthesis of Tryptamine Derivatives via a Direct, One‐Pot Reductive Alkylation of Indoles.

AbstractThe method can be used to synthesize melatonin (VIII) and luzindole (IIIe), an MT2 melatonin receptor antagonist.

ChemInform Abstract: Reductive Alkylation of Indoles with Alkynes and Hydrosilanes under Indium Catalysis.

AbstractA variety of indole derivatives is alkylated at the 3‐position with terminal and internal alkynes and hydrosilane as hydrogen nucleophile.

Reductive Alkylation of Indoles with Alkynes and Hydrosilanes under Indium Catalysis

Under Indium catalysis, diverse alkylindoles were successfully prepared with a flexible combination of indoles and alkynes in the presence of hydrosilanes. In addition to the hydrosilane, carbon nucleophiles are also available. This new method generates alkylindoles in yields over 70% with a broad scope of functional group compatibility.

A General Method for C3 Reductive Alkylation of Indoles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A general method for C 3 reductive alkylation of indoles

General indole C 3 reductive alkylation conditions have been developed. The scope of this reaction includes C 2 unsubstituted indoles, aryl and alkyl aldehydes, as well as N–H and N-alkyl indole substrates.

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°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.