22807-99-4Relevant academic research and scientific papers
Green, Mild, and Efficient Friedel–Crafts Benzylation of Scarcely Reactive Arenes and Heteroarenes under On-Water Conditions
La Manna, Pellegrino,Soriente, Annunziata,De Rosa, Margherita,Buonerba, Antonio,Talotta, Carmen,Gaeta, Carmine,Neri, Placido
, p. 1673 - 1683 (2019/03/26)
Metal-free Friedel–Crafts benzylation (FCB) of scarcely reactive arenes and heteroarenes was performed under on-water conditions by an environmentally sustainable procedure. The catalytic strategy exploits the hydrophobicity of the resorcinarene macrocycle 1 a. The proposed mechanism is based on the activation of benzyl chloride by H-bonding interactions with catalyst 1 a. In fact, under on-water conditions the hydrophobic amplification of the strength of the H-bonding interactions between the OH groups of the resorcinarene catalyst and the chlorine atom of benzyl chloride leads to polarization of the C?Cl bond, which consequently promotes electrophilic attack of the π nucleophile. Thus, many arenes and heteroarenes were efficiently benzylated under mild on-water conditions by using resorcinarene 1 a as catalyst. The FCB of benzene is industrially relevant for the synthesis of diphenylmethane, and hence the on-water procedure was extended to the gram-scale synthesis of diphenylmethane, starting from benzene and benzyl chloride in the presence of resorcinarene catalyst 1 a.
Mild Friedel–Crafts Reactions inside a Hexameric Resorcinarene Capsule: C?Cl Bond Activation through Hydrogen Bonding to Bridging Water Molecules
La Manna, Pellegrino,Talotta, Carmen,Floresta, Giuseppe,De Rosa, Margherita,Soriente, Annunziata,Rescifina, Antonio,Gaeta, Carmine,Neri, Placido
, p. 5423 - 5428 (2018/04/09)
A novel catalytic feature of a hexameric resorcinarene capsule is highlighted. The self-assembled cage was exploited to promote the Friedel–Crafts benzylation of several arenes and heteroarenes with benzyl chloride under mild conditions. Calculations showed that there are catalytically relevant hydrogen-bonding interactions between the bridging water molecules of the capsule and benzyl chloride, which is fundamental for the activation of the C?Cl bond. The capsule controls the reaction outcome. Inside the inner cavity of the capsule, N-methylpyrrole is preferentially benzylated in the unusual β-position while mesitylene reacts faster than 1,3-dimethoxybenzene despite the greater π-nucleophilicity of the latter compound.
INTRODUCTION OF ALKYL SUBSTITUENTS TO AROMATIC COMPOUNDS
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Page/Page column 63, (2016/09/15)
Novel selective synthesis route to introduce primary alkyl groups on aromatic compounds is disclosed. The synthesis route is based on electrophilic aromatic substitutions of thionium ion species that are generated in-situ from aldehydes and thiols, affording benzyl sulfide that can be reduced with triethylsilane.
Reductive Alkylation of Arenes by a Thiol-Based Multicomponent Reaction
Parnes, Regev,Pappo, Doron
supporting information, p. 2924 - 2927 (2015/06/30)
A simple and highly chemo- and regioselective method for introducing primary alkyl substituents into aromatic compounds was developed. The method is based on an electrophilic aromatic substitution of an aldehyde, promoted by a thiol, to afford 1-(alkylthio)alkylarenes, which can either be reduced in situ with triethylsilane or reacted further. This multicomponent reaction enables the direct introduction of both aromatic and linear and branched aliphatic alkyl groups into arenes. The above one-pot protocol may be performed in air and in the presence of water and is compatible with various functional groups.
Hydrosilanes are not always a reducing reagent: A ruthenium-catalyzed introduction of primary alkyl groups to electron-rich aromatic rings using esters as a source of the alkyl groups
Nagashima, Hideo,Kubo, Yuichi,Kawamura, Mitsunobu,Nishikata, Takashi,Motoyama, Yukihiro
supporting information; experimental part, p. 7667 - 7672 (2011/10/19)
A triruthenium cluster, (μ3, η2, η3, η5-acenaphthylene)Ru3(CO) 7 effectively catalyzes primary-alkylation reaction of electron-rich aromatic rings using a combination of hydrosilane and est
Pd(DPEPhos)Cl2-catalyzed Negishi cross-couplings for the formation of biaryl and diarylmethane phloroglucinol adducts
Dennis, Eric G.,Jeffery, David W.,Perkins, Michael V.,Smith, Paul A.
experimental part, p. 2125 - 2131 (2011/04/22)
Several functionalized biaryls and diarylmethanes containing the phloroglucinol subunit were synthesized in 55-85% yields using Negishi cross-couplings of 2,4,6-trimethoxyphenylzinc chloride with aryl and benzyl halides in the presence of catalytic quantities of Pd(DPEPhos)Cl2. These simple to prepare couplings were generally complete in 1-24 h depending on the halide, and were applicable to aryl and benzyl halides containing both electron-donating and electron-withdrawing groups.
B(C6F5)3: an efficient catalyst for reductive alkylation of alkoxy benzenes and for synthesis of triarylmethanes using aldehydes
Chandrasekhar,Khatun, Sanjida,Rajesh,Raji Reddy
experimental part, p. 6693 - 6697 (2010/01/18)
Tris(pentafluorophenyl)borane [B(C6F5)3] has been used as an efficient catalyst for reductive alkylation of alkoxy benzenes using aldehydes as an alkylating agent in the presence of polymethylhydrosiloxane (PMHS). Various alkylated trimethoxybenzene derivatives have been prepared in good to high yields. In addition, B(C6F5)3 was also used as a catalyst for the reaction of electron-rich arenes with aldehydes to obtain triarylmethanes. The use of reductive alkylation protocol for the synthesis of an isochroman and tetrahydroisoquinoline derivatives has also been demonstrated.
Subtle side-chain modifications of the hop phytoestrogen 8-prenylnaringenin result in distinct agonist/antagonist activity profiles for estrogen receptors α and β
Roelens, Frederik,Heldring, Nina,Dhooge, Willem,Bengtsson, Martin,Comhaire, Frank,Gustafsson, Jan-?ke,Treuter, Eckardt,De Keukeleire, Denis
, p. 7357 - 7365 (2007/10/03)
In search of therapeutic agents for estrogen-related pathologies, phytoestrogens are being extensively explored. In contrast to naringenin, 8-prenylnaringenin is a potent hop-derived estrogenic compound, highlighting the importance of the prenyl group for hormonal activity. We investigated the effects of substituting the prenyl group at C(8) with alkyl chains of varying lengths and branching patterns on estrogen receptor (ER) subtype ERα- and ERβ-binding affinities and transcriptional activities. In addition, features of the ligand-induced receptor conformations were explored using a set of specific ER-binding peptides. The new 8-alkylnaringenins were found to span an activity spectrum ranging from full agonism to partial agonism to antagonism. Most strikingly, 8-(2,2-dimethylpropyl)naringenin exhibited full agonist character on ERα, but pronounced antagonist character on ERβ. Knowledge on how ER-subtype-selective activities can be designed provides valuable information for future drug or tool compound discovery.
N-benzotriazoles: Preparation and Use in Synthesis
Katritzky, Alan R.,Lan, Xiangfu,Lam, Jamshed N.
, p. 1819 - 1826 (2007/10/02)
Methoxybenzenes and -naphthalenes are benzotriazolylmethylated in the para-position or if this is blocked in an ortho-position.The methylene groups in the products are readily substituted by electrophiles via the lithiated derivatives.Displacement ot the benzotriazole group can be effected by organometallic reagents or by electron-rich benzoid compounds to afford a versatile method for the synthesis of substituted aryl ethers.Key Words: Lithiation/ Grignard reaction/ Condensation/ Aryl ethers/ Diarylmethanes
