Themed collection Elegant Synthetic Routes to Indole Derivatives

Enantioselective 1,6-addition/1,4-addition cascade reactions between cyclic dienones and 2-indolnethiones have been realized, affording chiral spiro[thiopyranoindole-cyclohexanone] scaffolds facilely and efficiently.

Rosuvastatin based indoles showed anti-proliferative and apoptotic activities and an increase of p21 mRNA expression levels in zebrafish larvae.

Scandium triflate-catalyzed reactions between spiro-epoxyoxindole and carbonyl compounds have been disclosed. Furthermore, an unprecedented rearrangement takes place to yield alkylidene oxindoles when aromatic aldehydes are used as carbonyl components.

One-pot synthesis of β-indolylketones from saturated ketones and indoles was reported, which was useful in the synthesis of numerous heterocycles.

A synthetically useful reaction via NBS-mediated dinitrogen extrusion of N-aryl diazoacetamides under catalyst-free conditions is disclosed, which gives the 3-bromooxindoles in high to excellent yields with high selectivity via a non carbene process.

A direct approach to previously unexplored pyrrolizidino[1,2-b]indole system from indole-derived donor–acceptor cyclopropanes based on a sequence of three synthetic steps was developed.

Gold-catalyzed ring-opening reactions of oxygen-containing heterocycles.

Pyrano[3,4-b]indole fused quinoxalines were synthesized via an AlCl₃-mediated heteroarylation-cyclization method as potential anticancer agents.

A core scaffold for screening library production was synthesized in just four steps using a tandem Mannich/Diels–Alder sequence.

The reaction of indole and β-carbonyl nitrile to generate dicarbonyl indoles has been developed. This process involves α-oxonation of the β-carbonyl nitrile, Friedel–Crafts reaction with indoles and retro-cyanohydrination form dicarbonyl indoles.

The palladium-catalyzed oxidative arylation of indolines with arylsilanes at the C-7 position via C–H bond activation has been reported.

A novel rhodium(II)-catalyzed intramolecular annulation of 1-sulfonyl-1,2,3-triazoles with indoles has been developed, which enables the facile synthesis of various 4-functionalized tetrahydro-β-carbolines and relevant scaffolds from readily available starting materials.

Novel Mg(ClO₄)₂-promoted [4 + 3] cycloaddition reaction of oxindole derivatives and cyclopentadiene was achieved for the construction of the spirocycloheptane oxindole skeleton.

A novel effective protocol towards indolo[2,1-a]isoquinolinones via aryne-induced migration of aryl-anion in aryloxy substituted 3,4-dihydroisoquinolines is reported.

A fast selenylative spirocyclization of indolyl ynones mediated by PIFA has been developed. This transformation was enabled by the reactive RSeOCOCF₃ species generated in situ from diselenides with PIFA, involving an electrophilic dearomative cascade cyclization.

Upon gold catalysis, the 2,3-dihydropyrrolo[1,2-a]indole motif, encountered in few but interesting bioactive natural products, was efficiently obtained from N-aryl 2-alkynylazetidine derivatives.

An efficient metal-free, (NH₄)₂S₂O₈ mediated oxidative dearomatization of indoles for construction of C2-quaternary indolinones was disclosed which provides an approach for generation of all-carbon quaternary centers at the C2 position of indoles.

Functionalized graphitic carbon nitride (Sg-C₃N₄) has been manufactured and used as a reusable catalyst for the one-pot production of various spiro-pyrano chromenes and spiro indole-3,1′-naphthalene tetracyclic systems in aqueous media.

Under mild conditions, PIDA mediated oxidant C–N coupling to afford indolo[2,3-b]quinoline derivatives has been developed with a decent substrate scope.

Three-reactive centered reagent (TCCA) mediated construction of spirooxindoles through an oxidative rearrangement of various N-protected tetrahydro-β-carbolines and total synthesis of natural alkaloids (±)-coerulescine and (±)-horsfiline.

A Rh-catalyzed cascade annulation of N–H free 2-arylindole with benzoquinone via dual C–H activation strategy was reported.

The rhodium-catalyzed olefination and deuteration of tetrahydrocarbazoles in water with the aid of an N,N-dimethylcarbamoyl-protected group is presented.

17-nor-Excelsinidine was constructed via oxidative coupling in excellent yield and high regioselectivity under NBS/pyridine from the enolate of geissoschizine.

A simple and efficient asymmetric synthesis of THBCs through a chiral thiosquaramide 11b catalyzed imine reduction of dihydro-β-carbolines (17a−f) and syntheses of (−)-coerulescine and (–)-horsfiline via enantioselective oxidative rearrangement.

A Friedel–Crafts alkylation of indoles with β-(trifluoroacetyl)coumarins catalyzed by Sc(OTf)₃ to afford 1-(β-coumarinyl)-1-(β-indolyl)trifluoroethanols in a short time and high yield was developed.

A variety of N-unprotected 2-amide-substituted indoles were synthesized from readily available furfural-based Ugi adducts in moderate to good yields via palladium-catalyzed intramolecular cyclization of o-iodoanilines bearing furan rings.

Based on hemiindigos we developed novel reactions for producing γ-carbolines and their precursors that appeared to be active against MTB.

An efficient and practical procedure was developed to prepare 7-azaindole, starting from an o-haloaromatic amine and corresponding terminal alkynes under microwave irradiation and the scope was demonstrated with a number of examples.

A new method for the preparation of 2,2-disubstituted indolines from 2-phenylethylamines was developed under Pd catalysis and PhI(OAc)₂ as oxidant.

A general protocol for the synthesis of 2,2-disubstituted indolin-3-ones has been developed through self-dimerization of 2-aryl indoles and cross-addition with indoles under mild Cu-catalyzed oxidative conditions with good to high yields.

A short-step synthesis of N-benzyl matemone has been successfully carried out using a newly discovered 2-ethoxycarbonylindolin-3-one synthesis.

A simple and efficient approach to the synthesis of three new classes of fused spiropyridineoxindoles using heterocyclic ketene aminals.

An improved one-pot three-component synthesis involving electrophilically activated nitroalkanes allowed for efficient preparation of indoloquinolines with potent anticancer activities.

The first TfOH-catalyzed three-component Friedel–Crafts alkylation/ketalization sequence of indoles, alcohols and ortho-hydroxychalcones was developed to afford a wide range of 4-indole substituted chromans bearing a ketal motif in 77–99% yields.

Pd NCs serve recyclable and highly active catalyst to indole synthesis.

3-Arylindole derivatives were synthesized by Cu(I) catalysed intramolecular Ullmann coupling of 2-bromoarylaminoalkanes.

Nature has nourished β-carboline and isoxazole derivatives as privileged scaffolds and consequently they are ubiquitously found in alkaloids isolated from various sources.

A novel self-terminated Prins strategy has been developed for the synthesis of 2-substituted tetrahydropyran-4-one derivatives through a condensation of 3-(phenylthio)but-3-en-1-ol with carbonyl compounds in the presence of 5 mol% of Sc(OTf)₃ under mild conditions.

Copper catalyzed C-terminal and N-terminal attack of 2-alkynylanilines to 2-iodobenzamides afforded isoindolinones and 1,2-disubstituted indoles, respectively.

Palladium-catalyzed highly selective intramolecular addition of C–N and S–N bonds to alkynes has been achieved, and two distinct kinds of functional indoles were synthesized rapidly from the same set of substrates in a catalyst-controlled manner.

A collective formal synthesis approach to six bioactive oxindole alkaloids, including (±)-rhynchophylline and its five homologues, is completed in a highly efficient way.

L-Isoleucine derived bifunctional N-acylaminophosphine catalyzed a [3 + 2]-annulation reaction between allenyl carbonyl compounds and isatinimines to afford a facile and asymmetric access to 3,2′-dihydropyrrolyl spirooxindoles.

A Pd-catalysed β-carboline assisted decarboxylative acylation of ortho-C(sp²)–H of aryl ring of aryl(β-carbolin-1-yl)methanones using α-oxocarboxylic acid as the acyl ion source to form (2-aroylaryl)(β-carbolin-2-yl)methanones is demonstrated.

Rh(II)-catalyzed cycloaddition of 3-diazooxindoles with 2-methyl-2-(4-methylpent-3-en-1-yl)-2H-chromene-3-carbaldehydes has been developed to produce tetrahydro-3H,4H-spiro[furo[2,3-a]xanthene-2,3′-indolin]-2′-ones in good yields.

An operationally simple and environmental friendly approach to indole derivatives from N-Ts-2-alkenylanilines has been achieved, which involves an oxidative intramolecular C–H amination by using molecular oxygen as sole oxidant.

A cascade reaction has been developed for the direct and one-pot synthesis of 7H-indolo[3′,2′:4,5]furo[2,3-b]quinoxaline derivatives.

One pot two step synthesis of β-carbolinone and indolo-pyrazinone analogues via acid mediated cyclisation of Ugi intermediate has been developed with a wide substrate scope.