51601-26-4Relevant academic research and scientific papers
Palladium-Catalyzed Oxidative Allylation of Sulfoxonium Ylides: Regioselective Synthesis of Conjugated Dienones
Li, Chunsheng,Li, Meng,Zhong, Wentao,Jin, Yangbin,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 872 - 875 (2019/05/16)
The first examples of palladium-catalyzed allylic C-H oxidative allylation of sulfoxonium ylides to afford the corresponding conjugated dienones with moderate to good yields have been established. The features of this novel conversion include mild reaction conditions, wide substrate scope, and excellent regioselectivity.
Nickel-Catalyzed Cross-Coupling of Allyl Alcohols with Aryl- or Alkenylzinc Reagents
Yang, Bo,Wang, Zhong-Xia
, p. 4542 - 4549 (2017/05/12)
Nickel-catalyzed cross-coupling of allyl alcohols with aryl- and alkenylzinc chlorides through C-O bond cleavage was performed. Reaction of (E)-3-phenylprop-2-en-1-ol and 1-aryl-prop-2-en-1-ols with aryl- or alkenylzinc chlorides gave linear cross-coupling products. Reaction of 1-phenyl- or 1-methyl-substituted (E)-3-phenylprop-2-en-1-ol with aryl- or alkenylzinc chlorides resulted in 3-aryl/alkenyl-substituted (E)-(prop-1-ene-1,3-diyl)dibenzenes or 3-aryl/alkenyl-substituted (E)-(but-1-enyl)benzene. Reaction of allyl alcohol with p-Me2NC6H4ZnCl resulted in a mixture of normal coupling product 4-allyl-N,N-dimethylaniline and its isomerized product N,N-dimethyl-4-(prop-1-en-1-yl)aniline.
Flow Metal-Free Ar-C Bond Formation via Photogenerated Phenyl Cations
Bergami, Matteo,Protti, Stefano,Ravelli, Davide,Fagnoni, Maurizio
supporting information, p. 1164 - 1172 (2016/04/19)
A convenient photochemical flow protocol for the formation of aryl-carbon bonds via photogenerated phenyl cations has been developed. A wide range of phenylated products, including biaryls, allylarenes, 2-arylacetals and benzyl γ-lactones, was smoothly synthesized in satisfactory yields under metal-free conditions. The adoption of a flow reactor often allowed us to adopt higher concentrations of substrates and shorter irradiation times compared to those usually employed in batch systems.
Trifluoromethylchlorosulfonylation of alkenes: Evidence for an inner-sphere mechanism by a copper phenanthroline photoredox catalyst
Bagal, Dattatraya B.,Kachkovskyi, Georgiy,Knorn, Matthias,Rawner, Thomas,Bhanage, Bhalchandra M.,Reiser, Oliver
supporting information, p. 6999 - 7002 (2015/06/08)
Abstract A visible-light-mediated procedure for the unprecedented trifluoromethylchlorosulfonylation of unactivated alkenes is presented. It uses [Cu(dap)2]Cl as catalyst, and contrasts with [Ru(bpy)3]Cl2, [Ir(ppy)2(dtbbpy)]PF6, or eosin Y that exclusively give rise to trifluoromethylchlorination of the same alkenes. It is assumed that [Cu(dap)2]Cl plays a dual role, that is, acting both as an electron transfer reagent as well as coordinating the reactants in the bond forming processes. Double role: The trifluoromethylchlorosulfonylation of unactivated alkenes was developed using [Cu(dap)2]Cl as catalyst (dap=2,9-bis(para-anisyl)-1,10-phenanthroline). [Cu(dap)2]Cl plays a dual role; acting as an electron transfer reagent as well as coordinating the reactants in the bond forming processes.
Aryl imidazylates and aryl sulfates as electrophiles in metal-free ArSN1 reactions
Qrareya, Hisham,Protti, Stefano,Fagnoni, Maurizio
, p. 11527 - 11533 (2015/01/16)
Some oxygen-bonded substituents were investigated as leaving groups in photoinduced ArSN1 reactions. Irradiation of aryl imidazylates and of the corresponding imidazolium salts mainly caused homolysis of the ArO-S bond. However, previously unexplored trifluoroethoxy aryl sulfates were found to undergo efficient metal-free arylation. The sulfates were conveniently generated in situ by dissolving the corresponding imidazolium salts in basic 2,2,2-trifluoroethanol.
Solarylations via 4-aminophenyl cations
Dichiarante, Valentina,Fagnoni, Maurizio,Albini, Angelo
experimental part, p. 1271 - 1276 (2010/04/26)
(Chemical Equation Presented) The application of the photo-SN1 reaction on some 4-chloroanilines was explored under solar irradiation in view of obtaining a convenient metal-free arylation method. Several reactions previously carried out by UV irradiation, as well as some new ones, where either a new trap (α-methylstyrene) or a new halide (N,N-dimethyl-4- fluoroaniline) were adopted, were studied under these conditions and found to occur conveniently. Furthermore, at least in some cases the halide starting concentration could be raised up to 0.2 M, the excess trapping agent reduced from 20:1 to 2.5:1, and the solvent replaced by more environmentally friendly (co)solvents including water. Under these improved conditions, the photoarylation was carried out in a gram scale by merely exposing the solution to solar irradiation. This process has a low impact on the environment and can be considered a serious competitor of metal-catalyzed arylations. 2010 American Chemical Society.
Practical iron-catalyzed allylations of aryl grignard reagents
Mayer, Matthias,Czaplik, Waldemar M.,Von Wangelin, Axel Jacobi
supporting information; experimental part, p. 2147 - 2152 (2010/12/18)
An operationally simple iron-catalyzed reductive cross-coupling reaction between aryl halides and allyl electrophiles has been developed. The underlying domino process exhibits high versatility with respect to the allylic leaving group (acetate, tosylate, diethyl phosphate, methyl carbonate, trimethylsilanolate, methanethiolate, chloride, bromide) and high economic and environmental sustainability with respect to the catalyst system (0.2-5 mol% tris(acetylacetonato)iron(III), ligand-free) and reaction conditions (tetrahydrofuran, 0°C, 45 min).
Development of highly chemoselective bulky zincate complex, tBu 4ZnLi2: Design, structure, and practical applications in small-/macromolecular synthesis
Furayama, Taniyuki,Yonehara, Mitsuhiro,Arimoto, Sho,Kobayashi, Minoru,Matsumoto, Yotaro,Uchiyama, Masanobu
supporting information; experimental part, p. 10348 - 10356 (2009/10/10)
We present full details of the unique reactivities of the newly developed dianion-type bulky zincate, dilithium tetra-ferf-butylzincate (tBu 4ZnLi2). With this reagent, halogen-zinc exchange reaction of variously functionalized haloaromatics and anionic polymerization of N-isopropylacrylamide (NIPAm)/styrene with excellent chemoselectivity were realized. Halogen-zinc exchange reaction followed by electrophilic trapping with propargyl bromide provided a convenient route to functionalized phenylallenes, particularly those with electrophilic functional groups (such as cyano, amide and halogens). Spectral and computational studies of the structure in the gas and liquid phases indicated extraordinary stabilization of this dianion-type zincate by its bulky ligands.
Cross-coupling of aromatic bromides with allylic silanolate salts
Denmark, Scott E.,Werner, Nathan S.
supporting information; experimental part, p. 16382 - 16393 (2009/05/08)
The sodium salts of allyldimethylsilanol and 2-butenyldimethylsilanol undergo palladium-catalyzed cross-coupling with a wide variety of aryl bromides to afford allylated and crotylated arenes. The coupling of both silanolates required extensive optimization to deliver the expected products in high yields. The reaction of the allyldimethylsilanolate takes place at 85°C in 1,2-dimethoxyethane with allylpalladium chloride dimer (2.5 mol %) to afford 73-95% yields of the allylation products. Both electron-rich and sterically hindered bromides reacted smoothly, whereas electron-poor bromides cross-coupled in poor yield because of a secondary isomerization to the 1-propenyl isomer (and subsequent polymerization). The 2-butenyldimethylsilanolate (E/Z, 80:20) required additional optimization to maximize the formation of the branched (γ-substitution) product. A remarkable influence of added alkenes (dibenzylideneacetone and norbornadiene) led to good selectivities for electron-rich and electron-poor bromides in 40-83% yields. However, bromides containing coordinating groups (particularly in the ortho position) gave lower, and in one case even reversed, selectivity. Configurationally homogeneous (E)-silanolates gave slightly higher γ-selectivity than the pure (Z)-silanolates. A unified mechanistic picture involving initial γ-transmetalation followed by direct reductive elimination or σ-π isomerization can rationalize all of the observed trends.
Characterizing ionic liquids as reaction media through a chemical probe
Dichiarante, Valentina,Betti, Cecilia,Fagnoni, Maurizio,Maia, Angelamaria,Landini, Dario,Albini, Angelo
, p. 1834 - 1841 (2008/02/04)
The triplet N,N-dimethylaminophenyl cation, a highly reactive but chemospecific electrophile, has been used as a probe for characterizing the properties of reaction media for a series of imidazolium ILs. With the N-hexyl-N-methyl imidazolium derivatives (not with the W-butyl analogues), hydrogen transfer leading to the aniline was the main process. Trapping by iodide occurred with an inverse dependence on viscosity. Trapping by it nucleophiles exhibited a more complex behavior. This was explained by the effect of both the bulk viscosity and the structure of the IL cation on both steps of the reaction, namely, initial electrophilic attack and ensuing cation elimination or nucleophile addition. However, with an excellent nucleophile, such as thiophene, or when the latter step was intramolecular, as with 4-pentenol, the difference was obliterated and trapping became uniform. Incorporation of the probe into the IL cation (through insertion into the C-H bond a to the imidazolium ring) was demonstrated, while no addition to the anion tested (including bis(trifluoromethanesulfonimide)) took place.
