نتایج جستجو برای: friedel crafts
تعداد نتایج: 2494 فیلتر نتایج به سال:
A highly enantioselective Friedel-Crafts alkylation of pyrroles with 2-enoylpyridine N-oxides catalyzed by chiral PYBOX-DIPH-Zn(II) complexes has been developed. The catalyst offers substantial substrate scope and furnished alkylated pyrroles in excellent yields (up to 99%) and enantioselectivities (up to >99% ee).
The first highly efficient double Friedel-Crafts reaction of N-tosyl imines with anisole, phenol, thioanisole and analogues has been developed to produce the corresponding symmetric diarylmethanes and triarylmethanes with high regioselectivity in the presence of a catalytic amount of Bi(2)(SO(4))(3)-TMSCl at room temperature.
Novel and efficient Brønsted acid (p-TsOH) catalyzed inter- and intramolecular Friedel-Crafts alkylations have been developed to synthesize selenated three-component coupling and selenation-cyclization indole derivatives. Chemical removal of the phenylseleno moiety was investigated, and the reaction mechanisms were discussed.
1-Indanones have been successfully prepared by means of three different non-conventional techniques, namely microwaves, high-intensity ultrasound and a Q-tube™ reactor. A library of differently substituted 1-indanones has been prepared via one-pot intramolecular Friedel-Crafts acylation and their efficiency and "greenness" have been compared.
An inter- as well as intra-molecular thia-Pictet-Spengler cyclization of N-tethered thiols and vinylogous thiocarbonates is described for the stereoselective synthesis of N-fused thiazinoindole derivatives. The strategy is extended to one-pot, sequential Friedel-Crafts alkylation - Pictet-Spengler cyclization and the synthesis of thiazino-oxepino-indole.
A mild method for Friedel-Crafts acylation with aromatic and aliphatic carboxylic acids using cyanuric chloride, pyridine, and AlCl(3) was developed. Both inter- and intramolecular acylations were achieved at room temperature in high yield and in very short reaction times.
The direct functionalization of aromatic compounds, via Friedel-Crafts alkylation reactions with alcohols, is one of the cornerstones in organic chemistry. The present emerging area deals with the recent advances in the use of pi-activated alcohols in the catalytic and stereoselective construction of benzylic stereocenters.
Artificial metalloenzymes have emerged as an attractive new approach to enantioselective catalysis. Herein, we introduce a novel strategy for preparation of artificial metalloenzymes utilizing amber stop codon suppression methodology for the in vivo incorporation of metal-binding unnatural amino acids. The resulting artificial metalloenzymes were applied in catalytic asymmetric Friedel-Crafts a...
A novel acetyl chloride-mediated cascade transformation involving three components (benzyl carbamate, ethyl glyoxylate and arene nucleophiles) is reported. Aryl orthogonally protected α-amino acids are obtained in a one pot cascade, using a mild AcOH-AcCl system, via a critical autocatalytic dehydration-activation step ensuring an original and efficient Friedel-Crafts orchestration.
DNA-based catalysis can be used to control the enantioselectivity of copper-catalysed Diels-Alder and Friedel-Crafts reactions to produce either enantiomer of the product by changing the denticity of the ligand coordinated to the Cu(II) ion, even though the DNA adopts a right handed helical conformation only.
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