2756-97-0

Upstream product

• 487-89-8 Indole-3-carboxaldehyde 
• 96-32-2 bromoacetic acid methyl ester 
• 120-72-9 indole 
• 292638-85-8 acrylic acid methyl ester 
• 84186-34-5 C-(3-indolyl)-N-phenylnitrone 

Downstream Products

• 29953-71-7 3-β-indoleacrylic acid 
• 1158722-68-9 methyl 1-phenyl-9H-carbazole-3-carboxylate 

Relevant academic research and scientific papers

Pd(ii)/Lewis acid catalyzed regioselective olefination of indole with dioxygen

Transition metal ion catalyzed indole olefination through C-H activation is a convenient protocol to synthesize versatile bioactive vinylindole compounds; however, in most cases, stoichiometric amounts of oxidants were necessary to accomplish the catalytic cycle. The present study describes a Pd(ii)/LA (LA: Lewis acid) catalyzed indole olefination with dioxygen as the sole oxidant. The olefination reaction with electron-rich olefins proceeded smoothly through the pyrrolyl N-carboxamide group directed remote C-H activation at the C3 position of the indole with the Pd(ii)/LA catalyst, whereas Pd(ii) alone was a very sluggish catalyst under identical conditions. For the electron-deficient olefins, the directing N-carboxamide group was not essential for olefination with this Pd(ii)/LA catalyst, demonstrating a different olefination pathway from that of electron-rich olefins. Remarkably, 1H NMR kinetics disclosed that olefination proceeded much faster with electron-rich olefins than with electron-deficient ones.

Tandem [2 + 2] Cycloaddition/Rearrangement toward Carbazoles by Visible-Light Photocatalysis

Reported herein is the first example of the synthesis of carbazoles via oxidative cyclization of 3-alkenylindoles with styrenes under visible light. The irradiation of a catalytic amount of [Ir(dtbbpy)(ppy)2][PF6] as the photocatalyst enables various 3-alkenylindoles and styrenes to undergo tandem [2 + 2] cycloaddition/rearrangement, thereby leading to carbazole derivatives in good to excellent yields under aerobic conditions. Mechanistic studies reveal that photoinduced energy transfer followed by electron transfer is responsible for the tandem reaction.

Synthesis of 3-alkenylindoles through regioselective C-H alkenylation of indoles by a ruthenium nanocatalyst

3-Alkenylindoles are biologically and medicinally very important compounds, and their syntheses have received considerable attention. Herein, we report the synthesis of 3-alkenylindoles via a regioselective alkenylation of indoles, catalysed by a ruthenium nanocatalyst (RuNC). The reaction tolerates several electron-withdrawing and electron-donating groups on the indole moiety. Additionally, a robustness screen has also been employed to demonstrate the tolerance of several functional groups relevant to medicinal chemistry. With respect to the Ru nanocatalyst, it has been demonstrated that it is recoverable and recyclable up to four cycles. Also, the catalyst acts through a heterogeneous mechanism, which has been proven by various techniques, such as ICPMS and three-phase tests. The nature of the Ru nanocatalyst surface has also been thoroughly examined by various techniques, and it has been found that the oxides on the surface are responsible for the high catalytic efficiency of the Ru nanocatalyst.

Pd(II) supramolecular cage-catalyzed successive oxidative coupling: One-pot and regioselective synthesis of functionalized carbazoles from indoles

Carbazole is an important compound in pharmaceuticals and functional materials. A new Pd(II) supramolecular cage-catalyzed protocol for the synthesis of multifunctional carbazoles from indoles is described through regioselective successive oxidative Heck reactions. This new protocol is highly efficient, with a low Pd (2.4 mol%) catalyst loading and good compatibility for both N-H free and N-protected indole substrates. Moreover, it can be used to synthesize carbazoles with various functional groups by a one-pot two-step procedure. The excellent catalytic activity can be attributed to the distinct properties of the supramolecular cage structure in uniformly distributive and well-defined Pd(II) active centers on the cage surfaces.

MOFs Extend the Lifetime of Pd(II) Catalyst for Room Temperature Alkenylation of Enamine-Like Arenes

The synthesis of pharmaceutically relevant scaffolds, such as substituted indoles or uracils, through the alkenylation of the “enamine-like” aromatic C?H bond is performed at room temperature using catalytic amounts of Pd(OAc)2 in the presence

Formation and reductive ring opening reactions of indolyl-isoxazolidines: Access to novel natural product analogs and precursors

Regio- and stereoselective 1,3-dipolar cycloadditions of C-(3-indolyl)-N-phenylnitrone (2) with variedly substituted dipolarophiles were carried out to obtain syn- C4 and C5 substituted indolyl-isoxazolidines 6a-c and 7a-f, respectively. Reduction of obtained isoxazolidines, by employing various reducing agents, causes cleavage of the N-O bond, which is accompanied by concomitant cleavage of C-N bond leading to the formation of a library of novel indole based natural product analogs and precursors.

PdII-catalysed C-H functionalisation of indoles and pyrroles assisted by the removable N-(2-pyridyl)sulfonyl group: C2-alkenylation and dehydrogenative homocoupling

The easily installed and removed N-(2-pyridyl)sulfonyl group exerts complete C2 regiocontrol over the PdII-catalysed C-H alkenylation of indoles and pyrroles, affording the corresponding products in good isolated yields (typically ≥ 70%). A remarkable feature of this catalyst system is that it tolerates a wide variety of substituted alkenes, including conjugated electrondeficient alkenes, styrenes and 1,3- dienes, as well as conjugated 1,1- and 1,2-disubstituted olefins. The final reductive desulfonylation affords the C2- substituted, free-NH indoles and pyrroles in good yield. This N-(2-pyridyl)- sulfonyl-directing strategy has also been extended to the development of a protocol for the intermolecular, dehydrogenative homocoupling of indoles, providing 2,2'-biindoles. Mechanistic work based upon reactions with isotopically labelled starting materials and competitive kinetic studies of electronically varied substrates suggests a chelation- assisted electrophilic aromatic substitution palladation mechanism.

Polymer-assisted solution-phase synthesis under combined ultrasound and microwave irradiation: Preparation of α,β-unsaturated esters and carboxylic acids, key intermediates of novel sigma ligands

The optimal conditions to prepare α,β-unsaturated methyl esters via Wittig reaction combining polymer-assisted solution-phase synthesis (PASPS) methodology and simultaneous ultrasound and microwave irradiation were established. The effects of temperature, solvent, and irradiation time were discussed. Results clearly indicated the superiority of combined ultrasound and microwave-assisted procedure over microwave-assisted methodology. Moreover, an efficient PASPS procedure to prepare α,β-unsaturated carboxylic acids via tandem Wittig olefination and hydrolysis reaction was developed under combined ultrasound and microwave irradiation. Generally, a good conversion of aldehydes to acids was observed. The optimized protocols allowed us to quickly prepare a small collection of either α,β-unsaturated esters or carboxylic acids, key intermediates for the drug-discovery process of new sigma ligands. Copyright Taylor & Francis Group, LLC.