Friedel-Crafts Reaction Of Indoles Research Articles

Azobenzene derivatives of 3,3’-bis(indolyl)methanes: Novel electroactive materials with antioxidant activities

A practical and efficient synthesis of new electroactive azobenzene derivatives of bis(indolyl)methanes has been achieved via the Friedel-Crafts reaction of indole with 5-arylazosalicylaldehydes using propylphosphonic anhydride (T3P®) as an activating agent. This protocol is distinguished by its operational simplicity, high product yields, short reaction time, good functional group tolerance, and environmental friendliness. The antioxidant properties of the synthesized compounds were explored by examining their radical scavenging effect on DPPH radicals and their electrochemical redox behavior was assessed using cyclic voltammetry studies.

Chiral Macrocycle-Enabled Counteranion Trapping for Boosting Highly Efficient and Enantioselective Catalysis.

The tight binding enabled by tailor-made macrocycles can be manipulated for tuning the catalysis process. In parallel to well-developed crown ether-based cation-binding catalysis, a macrocycle-enabled counteranion trapping strategy is presented for boosting highly efficient and enantioselective catalysis. A set of bis-diarylthiourea macrocycles containing two BINOL moieties were designed and synthesized. They possess a well-confined chiral cavity and strong binding affinities towards disulfonate anions. Caused by the tight binding, just 1 mol % macrocycle in combination with 1 mol % ethanedisulfonic acid can promote excellent conversion and up to 99 % ee in the Friedel-Crafts reaction of indoles with imines. The acid or the macrocycle alone do not afford any reactivity. The high catalytic efficiency and excellent stereocontrol was ascribed to large, complexation-induced acidity enhancement and tight ion-pairing facilitated by cave-like macrocyclic cavity.

Enantioselective Friedel-Crafts Reaction of Indoles with N-Tosylimines Employing Takemoto's Organocatalyst

The asymmetric Friedel-Crafts reaction of indoles with imines provides a direct approach for the enantioselective construction of 3-indolyl methanamine derivatives. In this paper, a series of thiourea/ urea-tertiary amine derivatives have been used to catalyze the asymmetric F-C reaction of indoles with N-tosylimines. The effect of solvent, temperature and catalyst loading amount were investigated. the optimized conditions were determined to be toluene as the solvent with a 5 mol% loading of Takemoto's catalyst 1c at rt. A wide range of substituted indoles and imines were evaluated to explore the scope and general applicability of this reaction. The enantioselectivities were obviously affected by the position of the substituents on the phenyl ring of imines. 4- electron-donating substituted imines appeared to favor higher enantioselectivities. Moreover, indoles containing either electron-donating groups or electron-withdrawing groups were then investigated for the reaction with imines. In all cases, high yields and excellent enantioselectivities could be achieved. Of all the different substrates, the reaction of the 5-OMe substituted indole with 4-chloride substituted imine afforded an optimal yield and enantiomeric excess. Under the screened optimal condition, optically active 3-indolyl-methanamines were obtained in good yields (70-90%) with high enantioselectivities (up to 98%ee). The catalyst type and the substrate scope were broadened in this methodology.

A Facile Synthesis of Tris(indolyl)propanes by Concerted 1,2- and 1,4-Friedel-Crafts Attack of Indoles to α,β-Unsaturated Aldimines

The Friedel-Crafts reaction of indoles with a wide range of α,β-unsaturated aldimines catalysed by binaphthyl phosphoric acid is demonstrated. The resulting tris(indolyl)propanes are presumably generated by a concerted 1,2- and 1,4-nucleophilic attack to the conjugated imines. According to the preliminary bioassay results, the compound 4e exhibits moderate activity against pancreatic cancer cells.

Counteranions of In(Ⅲ) Induced Reversal of Enantiocontrol in Friedel-Crafts Reaction of Indoles by Asymmetric Binary Acid Catalysis

研究了双酸催化剂对吲哚和β,γ-不饱和α-酮酸酯的不对称Friedel-Crafts烷基化反应.金属铟(III)盐和手性磷酸组成的双酸催化体系可以高效、高选择性地催化吲哚与β,γ-不饱和α-酮酸酯的Friedel-Crafts烷基化反应.简单改变铟(III)盐的抗衡阴离子从F-到Br-,就能使产物的构型发生反转,并同时获得相应的高产率(最高达98%)和高对映选择性(最高大于99%)的1,4-加成产物.

Silica gel‐Mediated Friedel‐Crafts Reaction of Indoles with Functionalized Nitroallylic Acetates via an SN1 Process

AbstractAn environmentally friendly Friedel‐Crafts reaction was demonstrated between indoles and functionalized nitroallylic acetates in the presence of silica gel, providing the corresponding C‐3‐selective regioisomers in good to high overall chemical yields (70‐93%).

Research Progress in Friedel-Crafts Reaction of Indoles and Imines

Research Progress in Friedel-Crafts Reaction of Indoles and Imines

Friedel-Crafts Reaction of Indoles with Nitroalkenes Catalyzed by Mesoporous Material MCM-41

The Frieldel-Crafts reaction of indole with β-nitrostyrenes catalyzed by MCM-41 was studied. Application of this reaction led to produce 3-substituted indole derivatives being wide present in natural products. The method has several advan- tages of mild reaction, condition handling-up easily, environmental friendly and economic effects. The catalyst can be also recycled.

Copper-Catalyzed Asymmetric Friedel-Crafts Reaction of Indoles

Friedel-Crafts reactions of indoles can be used with a wide range of electrophiles, but few examples using methyl or ethyl trifluoro­pyruvate have been reported. The authors herein describe a copper bisoxazolidine catalyst that overcomes the long reaction times, limited substrate scope, and low selectivity seen in other catalyst systems.

Enantioselective Brønsted Acid Catalysis in the Friedel-Crafts Reaction of Indoles with Secondary ortho-Hydroxybenzylic Alcohols

The reaction of indole and various methyl-substituted indoles with the title compounds was studied in the presence of chiral phosphoric acids, which act as Bronsted acid catalysts. While yields were generally high (>90

Synthesis of New C2- Symmetric Fluoren-9-ylidene Malonate Derived Bis(oxazoline) Ligands and Their Application in Friedel-Crafts Reactions

A series of new C2-symmetric fluoren-9-ylidene malonate-derived bis(oxazoline) ligands were synthesized from fluoren-9-ylidene malonate and enantiomerically pure amino alcohols via a convenient route. Their asymmetric catalytic properties in the Friedel-Crafts reactions of indoles with arylidene malonates were evaluated, and the Cu(OTf)2 complex of a fluoren-9-ylidene malonate-derived bis(oxazoline) bearing a phenyl group showed moderate to good enantioselectivity (up to 88% ee).

Asymmetric Lewis Acid Catalysis of Aluminum(Salalen) Complexes: Friedel-Crafts Reaction of Indole

We examined the Lewis acid catalysis of chiral Al(salalen)X complexes and found that complex 1b (X = Br) serves as an efficient catalyst for the Friedel-Crafts reaction of indole with N-[(E)-alkenoyl]oxazolidin-2-ones. High enantioselectivity (up to 98% ee) was obtained under the optimized conditions.

Solventless Clay-Promoted Friedel−Crafts Reaction of Indoles with α-Amido Sulfones: Unexpected Synthesis of 3-(1-Arylsulfonylalkyl) Indoles

Friedel-Crafts reaction of indoles with alpha-amido sulfones in the presence of montmorillonite K-10 leads unexpectedly to 3-(1-arylsulfonylalkyl) indoles in good yield. The obtained products can be further desulfonylated under reductive or alkylative conditions giving linear and branched 3-substituted indoles.