Friedel-Crafts Acylations with Little or No Catalyst

Pearson, D. E.; Buehler, C. A.

doi:10.1055/s-1972-21912

Cited by 90 publications

(18 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Groups that encourage such ortho-lithiation include: strong activators, SO 2 NR 2 , NHCOR, CONR 2 , CSNHR, CONHR, OCONR 2 , CO 2 R, CH 2 NHCOR, CH 2 NHR, OCH 2 OMe; moderate activators, OR, NR 2 , SR, CF 3 , F; and weak activators, CH 2 OH, CH(OR) 2 . [12][13][14][15][16] The rapid expansion of the list of functionalities capable of directing lithiation has made this approach an important strategy for the synthesis of various regiospecifically substituted benzenes and heterocycles.…”

Section: Dmgmentioning

confidence: 99%

Reactions of organolithium reagents with quinazoline derivatives

El‐Hiti¹,

Hegazy²,

Alotaibi³

et al. 2012

Arkivoc

View full text Add to dashboard Cite

This review deals with directed and regioselective lithiation of various quinazoline derivatives by the use of alkyllithiums in anhydrous THF at low temperature. Reactions of the lithium reagents obtained from the lithiation reactions with a range of electrophiles give the corresponding substituted derivatives in high yields. The procedures are simple, efficient and general to provide derivatives which might be difficult to produce by other means. In some cases nucleophilic addition of alkyllithiums takes place to produce the corresponding addition products via 1,2-and 3,4-additions. In other cases nucleophilic substitution or halogen-lithium exchange reactions occur.

show abstract

Section: Dmgmentioning

confidence: 99%

Reactions of organolithium reagents with quinazoline derivatives

El‐Hiti¹,

Hegazy²,

Alotaibi³

et al. 2012

Arkivoc

View full text Add to dashboard Cite

show abstract

“…With some metal salts, however, an increase in reaction temperature sets them free from their complex with the ketone, and a true catalytic reaction becomes possible [73]; this is observed for iron(III) chloride [74] and some metal triflates [72,75], including their use under the action of MW heating [76].…”

Section: Acylation Of Aromatic Compoundsmentioning

confidence: 99%

“…The catalytic effect of graphite A thus depends on iron impurities, e. g. Fe 3 O 4 , and probably also on iron sulfides or sulfates, because sulfur is also present in this graphite, and all these iron compounds are known catalysts of FC acylation [69,73,74]. In this respect, it seems that FeCl 3 could be the true catalyst generated in situ by the reaction of the different iron compounds with acid chloride and hydrogen chloride.…”

Section: Entrymentioning

confidence: 99%

Microwave‐Assisted Reactions on Graphite

Laporterie

Marquié

Dubac

2002

Microwaves in Organic Synthesis

View full text Add to dashboard Cite

for the processing of polymers and composites in which carbon black or graphite particles or fibers are included in the material [9].The MW-promoted cracking of organic molecules in the presence of silica-supported graphite [10 a] or activated charcoal [10 b] has also been reported.Graphite, the most stable of the three allotropic forms of carbon, has two structures, a (hexagonal form) and b (rhombohedral form), which interconvert easily [11]. In a graphite layer, each carbon atom is strongly bonded to three other carbon atoms in a planar configuration (sp 2 hybridization), and the remaining p electrons (one per carbon) are delocalized. The resulting carbon±carbon bonds are very strong (477 kJ mol ± 1 ). The interlayer bonds, in contrast, are weak (17 kJ mol ±1 ), giving rise to the mechanical (lubricant) and chemical (intercalation) properties of graphite. Electronically, graphite is a semimetal of high electrical and thermal conductivity [11]. As for other semimetallic materials, the electronic current (s) is the main factor in the graphite±MW interaction [5]. The rate of heating of a MW-irradiated material has been estimated to be DT/t = s|E| 2 /rC, where E is the electric field, r is the density, and C is the specific heat capacity of the material [5]. Compared with other dielectric solids graphite has an unusually high thermal conductivity (a weak C, 0.63 kJ kg ±1 K ±1 at room temp.) [11]. This thermal conductivity, which decreases exponentially with increasing temperature, is a determining factor in the high rate of heating of graphite on MW irradiation, although other types of MW interaction, e. g. the excitation of weak interlayer bonds, and, especially in graphite powder, eddy currents or localized plasma effects, can also lead to very rapid dissipation of energy in graphite [5].Because of its strong coupling with MW, its good adsorbent properties towards organic molecules [12], and its layer structure which enables it to form intercalated compounds [13], graphite has great potential in MW-assisted synthetic applications in organic chemistry, despite its weak fractal dimension (D & 2) [14].Before the works of Laurent et al. [15,16], which described several examples of MWassisted organic syntheses in the presence of graphite other studies were reported in this field. Literature results are, therefore, very recent. They are presented here in two parts. The first concerns reactions in which graphite behaves as an energy converter (or ªsensitizerº) capable of conveying the energy carried by MW radiation to the chemical reagents. The second includes results which reveal surprising catalytic activity of some metal inclusions of graphite. Graphite as a SensitizerThis section covers reactions in which graphite is a sensitizer, without participation of its metal inclusions as possible catalysts, although a catalyst can be added to the graphite. The amount of graphite can be varied. It is generally at least equal to and most often greater than that of the reagents, resulting in a graphite-supported/microwave (GS/M...

show abstract

“…21 The remaining alkylbenzophenones were synthesized by adding the appropriate alkylphenyllithium reagent to benzaldehyde and oxidizing the resulting substituted benzhydrol to ketone with aqueous alkaline potassium permanganate. All compounds are known and were at least 99% pure as shown by GC-MS analysis.…”

Section: Compoundsmentioning

confidence: 99%

Structural changes in concentrated solutions of alkali metal monosubstituted benzophenone radical anions as deduced from ¹H NMR measurements

Micha-Screttas¹,

Heropoulos²,

Steele³

2001

Magnetic Reson in Chemistry

View full text Add to dashboard Cite

The radical anions of monosubstituted benzophenones (including 2-, 3-and 4-methyl-, 4-tert-butyl-and 4-phenylbenzophenone) with lithium, sodium and potassium as countercations in tetrahydrofuran (THF) were studied by paramagnetic solvent 1 H NMR shift measurements in the concentration range ca 0.1-1.0 M. In addition to the cation effects, marked positional isomer and substituent effects were found for (1) molar paramagnetism, (2) magnetic state, (3) solubility, (4) structural stability with respect to concentration or addition of cosolvents and (5) rapidity of attainment of their equilibrium structure. The major conclusions which can be drawn are (a) the solvation behavior of the countercation is governed by the anion, (b) an alkyl group in the 4-position makes the structure of the lithium and sodium monosubstituted benzophenone radical anions concentration dependent and (c) in most cases, alkali metal aromatic ketone radical anions generated by electron transfer from the corresponding naphthalene radical anion attain their equilibrium structure rapidly. The data are interpreted on the basis of the involvement of spin-triplet interactions within 'dimers' or higher clusters.

show abstract

Friedel-Crafts Acylations with Little or No Catalyst

Cited by 90 publications

References 0 publications

Reactions of organolithium reagents with quinazoline derivatives

Reactions of organolithium reagents with quinazoline derivatives

Microwave‐Assisted Reactions on Graphite

Structural changes in concentrated solutions of alkali metal monosubstituted benzophenone radical anions as deduced from ¹H NMR measurements

Contact Info

Product

Resources

About

Friedel-Crafts Acylations with Little or No Catalyst

Cited by 90 publications

References 0 publications

Reactions of organolithium reagents with quinazoline derivatives

Reactions of organolithium reagents with quinazoline derivatives

Microwave‐Assisted Reactions on Graphite

Structural changes in concentrated solutions of alkali metal monosubstituted benzophenone radical anions as deduced from 1H NMR measurements

Contact Info

Product

Resources

About

Structural changes in concentrated solutions of alkali metal monosubstituted benzophenone radical anions as deduced from ¹H NMR measurements