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Upstream product

• 67-56-1 methanol 
• 728-87-0 4,4'-Dimethoxybenzhydrol 
• 42240-30-2 bis-(4-methoxyphenyl)methyl acetate 
• 20114-55-0 4,4'-dimethoxybenzophenone hydrazone 
• 132417-64-2 methyl tris(4-methoxyphenyl)acetate 
• 958-80-5 bis(4-methoxyphenyl)thione 
• 116664-86-9 bis(4-methoxyphenyl)methyl 4-cyanophenyl ether 
• 7525-23-7 4,4'-dimethoxydiphenylmethyl chloride 
• 149-73-5 trimethyl orthoformate 
• 124-41-4 sodium methylate 
• 69545-37-5 di(p-anisyl)methyl bromide 

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• 67-56-1 methanol 
• 42240-30-2 bis-(4-methoxyphenyl)methyl acetate 
• 10543-21-2 1,1-bis(4-methoxyphenyl)ethane 
• 728-87-0 4,4'-Dimethoxybenzhydrol 

Relevant academic research and scientific papers

Site-Selective Alkoxylation of Benzylic C?H Bonds by Photoredox Catalysis

Methods that enable the direct C?H alkoxylation of complex organic molecules are significantly underdeveloped, particularly in comparison to analogous strategies for C?N and C?C bond formation. In particular, almost all methods for the incorporation of alcohols by C?H oxidation require the use of the alcohol component as a solvent or co-solvent. This condition limits the practical scope of these reactions to simple, inexpensive alcohols. Reported here is a photocatalytic protocol for the functionalization of benzylic C?H bonds with a wide range of oxygen nucleophiles. This strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C?O bonds with high site selectivity, chemoselectivity, and functional-group tolerance using only two equivalents of the alcohol coupling partner. This method enables the late-stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential applications in synthesis and medicinal chemistry.

Direct and Asymmetric Nickel(II)-Catalyzed Construction of Carbon-Carbon Bonds from N-Acyl Thiazinanethiones

A wide array of new N-acyl thiazinanethiones are employed in a number of direct and enantioselective carbon-carbon-bond-forming reactions catalyzed by nickel(II) complexes. The electrophilic species are mostly prepared in situ from ortho esters, methyl et

Iodine-catalyzed transformation of aryl-substituted alcohols under solvent-free and highly concentrated reaction conditions

Iodine-catalyzed transformations of alcohols under solvent-free reaction conditions (SFRC) and under highly concentrated reaction conditions (HCRC) in the presence of various solvents were studied in order to gain insight into the behavior of the reaction intermediates under these conditions. Dimerization, dehydration and substitution were the three types of transformations observed with benzylic alcohols. Dimerization and substitution reactions were predominant in the case of primary- and secondary alcohols, whereas dehydration prevailed in the case of tertiary alcohols. The relative reactivity of substituted 1-phenylethanols in I2-catalyzed dimerization under SFRC provided a good Hammett plot ρ+ = -2.8 (r2 = 0.98), suggesting the presence of electron-deficient intermediates with a certain degree of developed charge in the rate-determining step.

Stereoselective Alkylation of (S)-N-Acyl-4-isopropyl-1,3-thiazolidine-2-thiones Catalyzed by (Me3P)2NiCl2

The structurally simple (Me3P)2NiCl2 complex catalyzes SN1-type alkylations of chiral N-acyl thiazolidinethiones with diarylmethyl methyl ethers and other stable carbenium cations. The former can contain a varie

Solvolytic reactivity of pyridinium ions

The leaving group abilities of pyridine, 4-methylpyridine, and 4-chloropyridine in SN1 solvolytic reactions have been determined by analyzing the rate constants of X,Y-substituted benzhydrylpyridinium salts obtained in various solvents. By applying the linear free energy relationship equation, log k = sf (Ef + Nf), the nucleofuge specific parameters of 4-substituted pyridine have been extracted. Because of solvation in the reactant ground state, the reactivity (nucleofugality, Nf) of a given pyridine decreases as the polarity of the solvent increases. High slope parameters (sf > 1) may be due to the spread of the energy levels of the benzhydrylium ion/pyridine pair intermediates in comparison to benzhydrylium ion/chloride pairs (sf ≈ 1). Because of slow heterolysis step of pyridinium salts in various solvents, some are stable under normal conditions.

Competition of C-H and C-O fragmentation in substituted p-methoxybenzyl ether radical cations generated by photosensitized oxidation

Laser and steady-state photolysis, sensitized by 2,4,6-triphenylpyrylium tetrafluoroborate (TPP+BF4-), of 4-methoxybenzyl ethers [4-CH3O-C6H4CH(OR 1)R, 1a: R = H, R1 = CH3; 1b: R = H, R 1 = C(CH3)3; 1c: R = CH3, R 1 = C(CH3)3; 1d: R = 4-CH3O-C 6H4, R1 = CH3] was carried out in CH3CN in the presence of oxygen. In particular, steady-state irradiation of 1a, b and d produced benzylic alcohols (together with a small amount of acetamide for 1a and 1b) and the oxidation carbonyl compounds (esters and ketones); 4-methoxy-α-methylbenzyl alcohol was the only product observed with 1c. Time-resolved investigations of 1c and 1d gave evidence of the intermediate benzylic carbocation, coming from the ether radical cation formed within the laser pulse by an electron transfer process from the ether to the TPP+ excited state. These results suggested that, besides the deprotonation of the benzyl carbon, the cleavage of the C-OR1 bond is also operative in the reaction pathways of the ether radical cation. The comparison of these results with those obtained in the photolysis of 1c with the uncharged 9,10-dicyanoanthracene (DCA) upholds a particular behavior of TPP+BF4-, probably due to the specific electrostatic interactions of BF4- with the radical cation. This is also supported by quantum mechanical calculation results performed at the B3LYP/6-31G(d) level to obtain the charge and spin density distributions of radical cations, free and complexed with BF4 -.

Nucleofugality and nucleophilicity of fluoride in protic solvents

A series of p-substituted benzhydryl fluorides (diarylfluoromethanes) were prepared and subjected to solvolysis reactions, which were followed conductometrically. The observed first-order rate constants k1(25 °C) were found to follow the correlation equation log k1(25 °C) = sf(Nf + Ef), which allowed us to determine the nucleofuge-specific parameters Nf and sf for fluoride in different aqueous and alcoholic solvents. The rates of the reverse reactions were measured by generating benzhydrylium ions (diarylcarbenium ions) laser flash photolytically in various alcoholic and aqueous solvents in the presence of fluoride ions and monitoring the rate of consumption of the benzhydrylium ions by UV-vis spectroscopy. The resulting second-order rate constants k-1(20 °C) were substituted into the correlation equation log k-1 = sN(N + E) to derive the nucleophilicity parameters N and sN for fluoride in various protic solvents. Complete Gibbs energy profiles for the solvolysis reactions of benzhydryl fluorides are constructed.

Propagation rate of the cationic polymerization of 2,4,6-trimethylstyrene: A linear free energy approach

Kinetics of the reactions of benzhydryl cations with 2,4, 6-trimethylstyrene have been performed to determine its nucleophilicity parameters N = 0.68 and s = 1.09, which are comparable to styrene and considerably less nucleophilic than 4-methylatyrene, in

Solvent Nucleophilicity

The rates of the reactions of benzhydrylium ions (diarylcarbenium ions) with solvent mixtures of variable composition (water/acetonitrile, methanol/acetonitrile, ethanol/acetonitrile, ethanol/water, and trifluoroethanol/water) have been determined photometrically by conventional UV-vis spectroscopy, stopped-flow methods, and laser flash techniques. It has been shown that the first-order rate constants follow the previously published relationship log k(20°C) = s(N+E), where E is an empirical electrophilicity parameter, N is an empirical nucleophilicity parameter, and s is a nucleophile-specific slope parameter. From plots of log k versus E of the benzhydrylium ions are derived the solvent nucleophilicity parameters s and N, the latter of which are designated as N1 to emphasize that their use in the quoted correlation equation gives rise to first-order rate constants. A linear correlation between N1 and Kevill's solvent nucleophilicity NT based on S-methyldibenzothiophenium ions is reported, which allows one to interconvert the two sets of data. Because the N1 values are directly comparable to the previously reported nucleophilicity parameters N for π-systems (www.cup.uni-muenchen.de/oc/mayr/), the systematic design of Friedel-Crafts reactions with solvolytically generated carbocations becomes possible.

Photolysis of Triphenylacetic Acid and Its Methyl Ester: A Novel Photochemical Generation of Carbene Intermediates

The photolysis of methyl triphenylacetate in methanol gave biphenyl, methyl α-methoxyphenylacetate, methyl benzoate, and methoxydiphenylmethane.The formation of these products suggests that two types of α,α-elimination take place: One is the elimination of two phenyl groups leaving Ph-C-CO2Me (type a), and the other is the elimination of the phenyl and methoxycarbonyl groups generating Ph2C: (type b).Only type a elimination was efficiently quenched by oxygen.