FeCl3-catalyzed propargylation of aromatic compounds with propargylic acetates

A new method for the synthesis of propargylated aromatic compounds is developed. The reaction was carried out at room temperature in the presence of a catalytic amount of FeCl₃ in acetonitrile, high product yields were obtained with excellent regioselectivity and the reaction proceeded smoothly without exclusion of moisture or air.     

An efficient synthesis of diarylmethanes via InCl3·4H2O-catalyzed dehydration of electron-rich arenes with trioxane

A facile, efficient and environmentally benign procedure for the synthesis of diarylmethanes via the reaction of arenes with trioxane catalyzed by InCl₃·4H₂O was developed. The reactions of aromatic compounds bearing electron-donating group proceeded smoothly affording the corresponding diarylmethanes in good to excellent yields.     

Zirconyl chloride: an efficient recyclable catalyst for synthesis of 5-aryl-2-oxazolidinones from aziridines and CO2 under solvent-free conditions

Zirconyl chloride was found to be an efficient catalyst for the cycloaddition reaction of aziridines with CO₂, thus leading to the preferential formation of 5-aryl-2-oxazolidinones under solvent-free conditions. The methodology could be extended to various substituted aziridines with high conversion and chemo-, regio-, and stereoselectivity. Furthermore, the catalyst could be reused over five times without significant loss in activity. Interestingly, the recovered catalyst showed higher activity in comparison with the fresh catalyst, presumably due to its morphological variation. The use of this cheap and moisture stable catalyst make this protocol practical, environmentally benign, and economically attractive.     

First example of FeCl3-catalyzed alkylation of indoles with pinenes

Indoles undergo smooth alkylation with α- and β-pinenes in the presence of 20 mol % of anhydrous FeCl₃ under mild reaction conditions to produce a wide range of the corresponding 3-alkylated indoles in excellent yields with high trans-selectivity. This is the first example of alkylation of indoles with mono-terpenes.     

FeCl3-catalyzed alkylation of indoles with 1,3-dicarbonyl compounds: an expedient synthesis of 3-substituted indoles

Indoles undergo smooth alkylation at the 3-position with 1,3-dicarbonyl compounds in the presence of 20 mol % of FeCl₃ under mild reaction conditions to produce a wide range of 3-substituted indoles in excellent yields and with high E-selectivity.     

FeCl3-catalyzed functionalization of monoterpenes via hydroalkylation of unactivated alkenes

Monoterpenes such as α-pinene, β-pinene, limonene and isolimonene undergo smooth hydroalkoxylation in the presence of 20 mol % of FeCl₃ under mild reaction conditions to produce a wide range of the corresponding ethers in excellent yields and with high selectivity.     

One-pot solvent-free synthesis of triaryl- and triheteroarylmethanes by Bi(OTf)3-catalyzed Friedel-Crafts reaction of arenes/heteroarenes with trialkyl orthoformates

A convenient, practical and highly efficient one-pot method has been developed for the synthesis of triaryl- and triheteroarylmethane derivatives by Bi(OTf)₃-catalyzed Friedel-Crafts alkylation of trialkyl orthoformates in combination with a wide variety of arenes/heteroarenes at room temperature under solvent-free conditions and in an air atmosphere. The methodology offers an operational simplicity, high atom economy and environmentally benign procedure. Furthermore, selected compound 3k showed promising anti-inflammatory activity with inhibition nitric oxide and did not exhibit significant cytotoxic effects on macrophage cells.     

The use of anhydrous CeCl3 as a catalyst for the synthesis of 3-sulfenyl indoles

Anhydrous CeCl₃ was successfully used as a catalyst for the synthesis of several 3-sulfenyl indoles in good to excellent yields through the reaction of indole with N-(alkylthio) and N-(arylthio)phthalimides in DMF.     

Rice-husk-supported FeCl3 nano-particles: Introduction of a mild,efficient and reusable catalyst for some of the multi-component reactions

Rice-husk-supported FeCl₃ nano-particles (FeCl₃–RiH) were prepared and used as an environmentally friendly catalyst in the synthesis of β-amino carbonyl compounds, 1,8-dioxo-octahydro xanthenes, and bis-indolyl methanes from simple and readily available precursor molecules.     

ZrCl4 as a mild and efficient catalyst for the one-pot conversion of TBS and THP ethers to acetates

A mild, efficient and chemoselective method has been developed for the direct transformation of tert-butyldimethylsilyl and tetrahydropyranyl protected alcohols into the corresponding acetates with acetic anhydride and zirconium(IV) chloride as the catalyst in acetonitrile, in a one-pot reaction with high yields and short reaction times. This method has been applied to a variety of substrates.     

FeCl3·6H2O-promoted skeleton-rearrangement of 1-substituted-3-benzazepines: substrate extension and product utilization

FeCl₃·6H₂O-promoted skeleton-rearrangement of 1-substituted-3-benzazepines was further exploited. Both 1-aryl- and 1-alkyl- or 1-alkenyl-benzazepines underwent this reaction smoothly. The rearrangement products were used to prepare a series of novel derivatives containing both tetrahydroisoquinoline (THIQ) and tetrahydropyrimidin-4(1H)-one scaffolds through a Mannich-type process.     

Catalytic hydroarylation of alkynes with arenes in the presence of FeCl3 and AgOTf

Hydroarylation of propiolic acids with various arenes in TFA proceeded efficiently in the presence of FeCl₃/AgOTf catalyst system. In the case of electron-rich arenes, the iron-catalyzed hydroarylation gave cinnamic acids in moderate to high yields. The hydroarylation of phenylacetylene was observed but the catalyst was not effective under the same conditions.     

IrCl3 or FeCl3-catalyzed convenient synthesis of 3-hydroxyphthalates

IrCl₃·3H₂O or FeCl₃-catalyzed convenient synthesis of 3-hydroxyphthalates has been achieved by a Diels-Alder reaction of furans with dimethyl acetylenedicarboxylate, followed by ring-opening aromatization reaction of the Diels-Alder adducts, 7-oxabicyclo[2.2.1]hepta-2,5-diene derivatives. In addition, 7-azabicyclo[2.2.1]hepta-2,5-diene derivative, derived from N-Boc-pyrrole and dimethyl acetylenedicarboxylate, also converted into 3-aminophthalate derivative.     

Iodine-catalyzed Friedel-Crafts alkylation of electron-rich arenes with aldehydes: efficient synthesis of triarylmethanes and diarylalkanes

Iodine is shown to be an efficient catalyst for the Friedel-Crafts alkylation of arenes with a wide variety of aldehydes in toluene under ‘open-flask’ and mild conditions. In the presence of 10 mol % of iodine, the reaction of arenes with aromatic aldehydes gives the corresponding triarylmethane derivatives (TRAMs), regioselectively, in good to excellent yields. On the other hand, a series of diarylalkane derivatives is synthesized smoothly by the reaction with aliphatic aldehydes.     

An eco-friendly synthesis of 2-aminochromenes and indolyl chromenes catalyzed by InCl3 in aqueous media

A simple and convenient method for the synthesis of new 2-aminochromenes and indolyl chromenes via an indium trichloride catalyzed, three-component reaction in aqueous media is described.     

A simple access to triarylmethane derivatives from aromatic aldehydes and electron-rich arenes catalyzed by FeCl3

Under ‘open-flask’ and mild conditions, arenes condense smoothly with aromatic aldehydes in the presence of catalytic amount of FeCl₃. The reaction tolerated a variety of substitutions and functional groups. This method provides a facile and direct access to symmetrical and unsymmetrical triarylmethane derivatives.     

Syntheses and X-ray crystal structures of [Co(η-CO3)(NH3)4](NO3)·0.5H2O and [(NH3)3Co(μ-OH)2(μ-CO3)Co(NH3)3][NO3]2·H2O

[Co(η²-CO₃)(NH₃)₄](NO₃)·0.5H₂O and [(NH₃)₃Co(μ-OH)₂(μ-CO₃)Co(NH₃)₃][NO₃]₂·H₂O were prepared by prolonged aerial oxidation of a solution of Co(NO₃)₂·6H₂O and ammonium carbonate in aqueous ammonia. The formation of these side products highlights the richness of the chemistry of these systems and the possibility of by products if methods are not strictly adhered to. The X-ray crystal structures of [Co(η²-CO₃)(NH₃)₄][NO₃]·0.5H₂O and [(NH₃)₃Co(μ-OH)₂(μ-CO₃)Co(NH₃)₃][NO₃]₂·H₂O reveal a monomeric octahedral cobalt center with η²-bound CO₃²⁻ in the former, while the latter consists of a dimeric array where the two cobalt centers are bridged by two OH⁻ and one μ₂-CO₃²⁻ groups with three terminal NH₃ ligands for each Co center. In both complexes extensive hydrogen bonding interactions are evident.     

Anhydrous CeCl3 catalyzed C3-selective propargylation of indoles with tertiary alcohols

Anhydrous CeCl₃ was successfully used as catalyst for the synthesis of several 3-propargyl indoles in good yields through the reaction of indole with propargyl alcohols in nitromethane.     

Glycerin and CeCl3·7H2O: a new and efficient recyclable medium for the synthesis of bis(indolyl)methanes

Glycerin and CeCl₃·7H₂O were successfully used in recyclable catalytic system for the synthesis of several bis(indolyl)methanes in good to excellent yields through the reaction of indoles with aldehydes. The method is applicable to aliphatic and aromatic aldehydes, and the mixture of glycerin and CeCl₃·7H₂O can be reused up to five times without special treatment and with comparable yields.     

Vanadium(III) chloride as an effective catalyst for the Pechmann reaction

Good yields of substituted coumarins were obtained by a synthetic method involving the Pechmann reaction using vanadium(III)chloride (VCl₃) reagent to effect this condensation under solvent-free conditions. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 197–200, February, 2006.