5789-33-3

Upstream product

• 2051-18-5 4-isopropylbenzyl chloride 
• 434-45-7 2,2,2-Trifluoroacetophenone 
• 99-87-6 4-methylisopropylbenzene 
• 5623-24-5 4,4'-diisopropylbenzoin 
• 79135-52-7 1,2-bis(4-isopropylphenyl)acetylene 
• 64-19-7 acetic acid 
• 107-13-1 acrylonitrile 
• 82234-68-2 p-dichloromethylcumene 
• 79135-55-0 1,2-Dichloro-1,2-bis(p-isopropylphenyl)ethane 
• 73789-86-3 4-i-propylbenzyl bromide 
• 202277-65-4 1,2-bis[(2,4,6-trimethylphenyl)imino]-1,2-dimethylethane 
• 1337556-97-4 C₁₈H₂₀O 
• 4395-87-3 (4-isopropylphenyl)acetonitrile 
• 101-97-3 Ethyl 2-phenylethanoate 

Relevant academic research and scientific papers

Mechanistic Insights into Concerted C-C Reductive Elimination from Homoleptic Uranium Alkyls

A mechanistic study was carried out to probe concerted C-C reductive elimination from homoleptic uranium(IV) alkyls. The para-chloro uranium(IV) tetrabenzyl derivative, U(CH2-p-ClC6H4)4 (2-p-Cl), was synthesized by treating UCl4 with 4 equivalents of KCH2-p-Cl-Ph (1-p-Cl) at 108 °C, adding a new member to the previously reported family of uranium alkyl complexes U(CH2C6H5)4 (2-Bn), U(CH2-p-iPrC6H4)4 (2-p-iPr), U(CH2-ptBu-C6H4)4 (2-p-tBu), U(CH2-o-OMeC6H4)4 (2-o-OMe), and U(CH2-m-OMeC6H4)4 (2-m-OMe). Each member of this family readily reacts with the redox-active α-diimine ligand, MesDABMe (MesDABMe = [MesN = C(Me)C(Me) = NMes]; Mes = 2,4,6-trimethylphenyl), to afford the products from C-C reductive elimination, namely, (MesDABMe)U(CH2Ph′)2 and Ph′CH2CH2Ph′ (Ph′ = p-iPrC6H4, p-tBuC6H4, m-OMeC6H4, p-ClC6H4). Room-temperature magnetic-susceptibility values, obtained via SQUID magnetometry, show a correlation with an increase in the magnetic moment as the electron-withdrawing character of the substituent increases. Kinetic studies were used to assess the effect of the benzyl substituent on the rate of reductive elimination, showing that reaction rate increases as the electron-withdrawing nature of the substitution increases. Eyring data revealed a large and negative entropy value, indicative of a highly ordered transition state, consistent with the previously reported concerted elimination concluded from crossover experiments.

A well-defined low-valent cobalt catalyst Co(PMe3)4 with dimethylzinc: a simple catalytic approach for the reductive dimerization of benzyl halides

Herein, we report the first catalytic version of a cobalt-catalysed reductive homocoupling of benzyl halides which proceeds with low catalyst loadings (0.5 to 5 mol%). By synthetizing each cobalt intermediate we demonstrate that reaction proceeds through two single electron transfers (SET) and that dimethylzinc is only involved in the regeneration of the catalytic species.

Cyclopentadienyl nickel(ii) N, C-chelating benzothiazolyl NHC complexes: Synthesis, characterization and application in catalytic C-C bond formation reactions

Cyclopentadienyl (Cp) Ni(ii) complexes [CpNiL][PF6] containing hybrid N,C chelating benzothiazolyl NHC ligands (L1 = 1-(2-benzothiazolyl)-3-methylimidazol-2-ylidene, 3a; L2 = 1-(2-benzothiazolyl)-3-allylimidazol-2-ylidene, 3b; L3 = 1-(2-benzothiazolyl)-3-benzylimidazol-2-ylidene, 3c) have been synthesized and fully characterized. The catalytic activity of 3a-3c in some C-C bond formation reactions has been examined. They are efficient catalysts for the homo-coupling of benzyl bromide in the presence of MeMgCl at r.t. with good functional group tolerance. Complex 3a is active in the catalytic oxidative homo-coupling of Grignard reagents with 1,2-dichloroethane as an oxidant at r.t.

Facile and efficient reductive homocoupling of benzyl and aryl halides catalyzed by ionic liquid [C12mim][CuCl2] in the presence of metallic zinc and copper

A facile and efficient synthesis of bibenzyl and biaryl derivatives by reductive homocoupling reaction is described. Treatment of benzyl and aryl halides with metallic zinc and copper powder in the presence of a catalytic amount of [C12mim][CuCl2] under ligand- and base-free conditions gives the corresponding bibenzyls and biaryls in good to high yields. The product can be isolated by a simple extraction with organic solvent, and the catalytic system can be recycled or reused without any significant loss of catalytic activity.

Unsurpassed cage effect for the photolysis of dibenzyl ketones in water-soluble dendrimers

Amphiphilic water-soluble poly(alkyl aryl ether) dendrimers Gn (n = 1-3) with charge-neutral tetraethylene glycol monomethyl ethers at their periphery were synthesized as microreactors to control the photochemical reactions of dibenzyl ketone derivatives in aqueous solutions. Photophysical studies demonstrated that Gn can encapsulate organic molecules and provide a hydrophobic microenvironment. The product distribution of photolysis of dibenzyl ketone derivatives can be successfully controlled by encapsulating the substrates within dendrimers, and an unsurpassed cage effect of 1.00 is reached in high generation dendrimers, revealing that a thick and compact "shell" was formed at the periphery of the dendrimers. The cage effect is also significantly influenced by the substituent at the para-position of the guest molecules. The higher generation dendrimers exhibit a better confined microenvironment and the aggregates possess more compact cavities to "lock" the guests than the corresponding unimolecular dendrimers. After photolysis, the separation of products can be easily achieved by extracting from the dendrimer solutions and the dendrimers are simply recovered and reused.

Photochemical Hydrogen Abstraction from Cymenes

The three isomeric cymenes are examined in photochemical reactions involving hydrogen transfer with 1,4-naphthalenedicarbonitrile (NDN), α,α,α-trifluoroacetophenone (TFA), and benzophenone (BP).Selectivity for attack at primary vs tertiary position (P/T) and quantum yield are determined.The reactions are rationalized as involving loose perpendicular complexes yielding a low P/T ratio in the products (with BP n? triplet), a face-to-face charge transfer complex yielding a high P/T (with TFA ??* triplet and also NDN singlet, but only as far as the benzylnaphthalenes 1 and 2 are concerned), and a tighter charge transfer complex yielding again a low P/T in the formation of dibenzomethanocyclooctenes 3, the main products from NDN.The energetic limit of such a directing effect of the conformation of the intermediate complex onto photochemical reactivity is evidenced by the different results obtained with o-cymene.

HYDROGEN ABSTRACTION FROM THE ISOMERIC CYMENES

The irradiation of cerium (IV) ammonium nitrate in the presence of ortho, meta and para cymene yields products from attack at the methyl group (the nitrates - these ones in 55 to 69percent isolated yield-, the nitro derivatives, and the aldehydes) as well as at the isopropyl group (the acetophenones, not obtained from the ortho isomer), with minimal ring nitration.The formation of bibenzyls on irradiation with t-butyl peroxide of the same substrates is also studied.The mechanisms of the reactions with the NO3 radical, a good electron acceptor, and with the alkoxy radical are contrasted and compared with photochemical hydrogen abstraction by n?* and, respectively, ??* excited states.

CYANOETHYLATION OF HYDROCARBONS, INITIATED BY AUTOOXIDATION

Oxygen was used as an initiator of the free-radical cyanoethylation of alkylbenzenes (toluene, o-, m-, and p-xylenes, mesitylene, ethylbenzene, p-cymene) and tetralin (0.25-0.66 liter of oxygen to 1 liter of the hydrocarbon) The reactions were carried out in an autoclave at 150-350 deg C with a carbon-acrylonitrile ratio of 100:1.The initiation evidently results mainly from homolytic dissociation of the hydroperoxide formed during the autooxidation of the hydrocarbons.The effectiveness of oxygen for the initiation of the cyanoethylation of hydrocarbons depends on the oxidizability of the hydrocarbons.

Extent of Charge Transfer in the Photoreduction of Phenyl Ketones by Alkylbenzenes

Rate constants for triplet-state reaction of various ring-substituted benzophenones (BPs), acetophenones (APs), and α,α,α-trifluoroacetophenones (TFAs) with toluene and p-xylene have been determined by a combination of flash kinetics, steady-state quenching, and quantum yield measurements.The relative amounts of primary and tertiary radicals formed by reaction of the same ketons with p-cymene have also been measured.For all three types of ketones, rate constants correlate well with triplet ketone reduction potentials.The magnitude of the kinetic isotope effects observed with toluene-d8 and p-xylene-d10 diminishes as the ketones become easier to reduce.All of the ketone triplets react with alkylbenzenes primarily by a charge-transfer mechanism, with the rate-determining step changing from complexation to hydrogen transfer as the ketones become harder to reduce.The least reactive AP triplets probably react significantly via simple hydrogen atom abstraction as well.Those ketones with n,?* lowest triplets (all BPs and some APs) react with p-cymene to give primary/tertiary radical ratios that vary no more than a factor of 2 from the 0.40 value displayed by tert-butoxy radicals; those with ?,?* lowest triplets (TFAs and some APs) give ratios that favor primary radicals and that vary by an order of magnitude with the triplet ketone reduction potential.The variation in cymene product ratios reflect different orientations for attack on cymene by n,?* and ?,?* triplets and differing degrees of partial electron transfer within the exciplexes, which are not tight radical ion pairs.The variation seen for ?,?* triplets represents a stereoelectronic effect within face-to-face exciples, as evidenced by the excerptional behavior of p-diacylbenzenes, which give the highest ratio of tertiary radicals from cymene.There is no set intrinsic ratio of reactivity for ?,?* triplets vs. n,?* triplets in these CT reactions.The two types of triplets show similar reactivity for the more easily reduced triplets, with the harder to reduce ?,?* triplets being only one-tenth as reactive as n,?* triplets of comparable triplet reduction potential.When the extent of electron transfer in the exciplex is small, hydogen transfer is rate determining and ?,?* reactivity drops.A study of two radical reactions which generate benzyl and α-hydroxy-α-methylbenzyl radicals indicates that radical disproportionation cannot explain the low quantum yields (0.10) of most ketone-toluene photoreductions, which apparently involve substantial radiation less decay by the exciplex intermediates.

Hydrogenation Reactions of Some Spool-Shaped Acetylenes

The spool-shaped acetylenes bis(p-isopropylphenyl)acetylene (1a) and bis(p-tert-butylphenyl)acetylene (1b) have been synthesized and rigorously characterized.Their hydrogenation reactions have been studied.These acetylenes add hydrogen smoothly in solution, but at low pressures they do not add hydrogen on the metallic catalysts platinum, palladium, and nickel.This anomaly is explained in terms of the postulate that the isopropyl and tertiary butyl groups prevent the CC group from resting flatly upon the catalyst.The simple structure of these molecules provides a crude estimate of the minimum critical distance of approach of the unsaturated moiety of the molecule to the surface of the metallic catalyst for effective hydrogenation.