- Pd(II)-catalyzed P(O)R1R2-directed asymmetric C-H activation and dynamic kinetic resolution for the synthesis of chiral biaryl phosphates
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An efficient method of Pd(II)-catalyzed P(O)R1R2-directed asymmetric C-H activation and dynamic kinetic resolution for synthesis of chiral phosphinate ligands has been performed and exhibits a wide scope of substrates and an excellen
- Ma, Yan-Na,Zhang, Hong-Yu,Yang, Shang-Dong
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- Synthesis of Polybenzoacenes: Annulative Dimerization of Phenylene Triflate by Twofold C?H Activation
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Polycyclic aromatic hydrocarbons (PAHs) represent an emerging class of π-conjugated molecules in the area of optoelectronic devices and materials. Unprecedented synthetic routes to various PAHs from simple phenol derivatives by a palladium-catalyzed annulative dimerization of phenylene triflate through twofold inter- and intramolecular C?H activation have been established. The initially formed partially fused PAHs can be smoothly transformed into a variety of fully fused PAHs by the Scholl reaction. Furthermore, the reactions of phenanthrene-substituted aryl triflates proceeded regioselectively. The findings inspired the development of a rapid and efficient synthesis of polybenzoacene derivatives. This study not only allows transformation of phenyl triflates, but also discloses a new retrosynthetic strategy towards PAHs, especially polybenzoacenes.
- Uryu, Mizuho,Hiraga, Taito,Koga, Yoshito,Saito, Yutaro,Murakami, Kei,Itami, Kenichiro
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- SuFEx-enabled, chemoselective synthesis of triflates, triflamides and triflimidates
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Sulfur(vi) Fluoride Exchange (SuFEx) chemistry has emerged as a next-generation click reaction, designed to assemble functional molecules quickly and modularly. Here, we report the ex situ generation of trifluoromethanesulfonyl fluoride (CF3SO2F) gas in a two chamber system, and its use as a new SuFEx handle to efficiently synthesize triflates and triflamides. This broadly tolerated protocol lends itself to peptide modification or to telescoping into coupling reactions. Moreover, redesigning the SVI-F connector with a SO → SNR replacement furnished the analogous triflimidoyl fluorides as SuFEx electrophiles, which were engaged in the synthesis of rarely reported triflimidate esters. Notably, experiments showed H2O to be the key towards achieving chemoselective trifluoromethanesulfonation of phenols vs. amine groups, a phenomenon best explained - using ab initio metadynamics simulations - by a hydrogen bonded termolecular transition state for the CF3SO2F triflylation of amines. This journal is
- Alonso, Mercedes,De Borggraeve, Wim M.,Demaerel, Joachim,Hoppenbrouwers, Fien,Li, Bing-Yu,Van Lommel, Ruben,Verhelst, Steven H. L.,Voets, Lauren
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p. 2270 - 2279
(2022/03/08)
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- Bismuth-Catalyzed Oxidative Coupling of Arylboronic Acids with Triflate and Nonaflate Salts
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Herein we present a Bi-catalyzed cross-coupling of arylboronic acids with perfluoroalkyl sulfonate salts based on a Bi(III)/Bi(V) redox cycle. An electron-deficient sulfone ligand proved to be key for the successful implementation of this protocol, which allows the unusual construction of C(sp2)-O bonds using commercially available NaOTf and KONf as coupling partners. Preliminary mechanistic studies as well as theoretical investigations reveal the intermediacy of a highly electrophilic Bi(V) species, which rapidly eliminates phenyl triflate.
- Cornella, Josep,Peciukenas, Vytautas,Planas, Oriol
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supporting information
p. 11382 - 11387
(2020/07/14)
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- Rapid Room-Temperature, Chemoselective Csp2?Csp2Coupling of Poly(pseudo)halogenated Arenes Enabled by Palladium(I) Catalysis in Air
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While chemoselectivities in Pd0-catalyzed coupling reactions are frequently non-intuitive and a result of a complex interplay of ligand/catalyst, substrate, and reaction conditions, we herein report a general method based on PdIthat allows for an a priori predictable chemoselective Csp2?C Csp2coupling at C?Br in preference to C?OTf and C?Cl bonds, regardless of the electronic or steric bias of the substrate. The C?C bond formations are extremely rapid (Idimer under open-flask conditions.
- Kalvet, Indrek,Magnin, Guillaume,Schoenebeck, Franziska
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supporting information
p. 1581 - 1585
(2017/02/05)
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- Ligand- and Solvent-Tuned Chemoselective Carbonylation of Bromoaryl Triflates
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The palladium-catalyzed chemoselective carbonylation of bromoaryl triflates is reported. The selective C?Br bond versus C?OTf (OTf=triflate) bond functionalization can be remarkably tuned by the combination of the ligand [4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (Xantphos) vs. 1,1′-bis(diphenylphosphino)ferrocene (DPPF)] and the solvent (toluene vs. DMSO). The respective ligand and solvent effects are rationalized by DFT calculations. In contrast, the monodentate ligands BuPAd2 and tBu3P prefer the selective C?Br bond activation and are solvent insensitive.
- Shen, Chaoren,Wei, Zhihong,Jiao, Haijun,Wu, Xiao-Feng
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supporting information
p. 13369 - 1337
(2017/09/06)
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- Access to Air-Stable 1,3-Diphosphacyclobutane-2,4-diyls by an Arylation Reaction with Arynes
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Tuning of the physicochemical properties of the 1,3-diphosphacyclobutane-2,4-diyl unit is attractive in view of materials applications. The use of arynes is shown to be effective for installing relatively electron rich aryl substituents into the open-shell singlet P-heterocyclic system. Treatment of the sterically encumbered 1,3-diphosphacyclobuten-4-yl anion with ortho-silylated aryl triflates in the presence of fluoride under appropriate conditions afforded the corresponding 1-aryl 1,3-diphosphacyclobutane-2,4-diyls. The air-stable open-shell singlet P-heterocycles exhibit considerable electron-donating character, and the aromatic substituent influences the open-shell character, which is thought to be related to the property of p-type semiconductivity. The P-arylated 1,3-diphosphacyclobutane-2,4-diyl systems can be further utilized as detectors of hydrogen fluoride (HF), which causes a remarkable change in their photoabsorption properties.
- Ueta, Yasuhiro,Mikami, Koichi,Ito, Shigekazu
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supporting information
p. 7525 - 7529
(2016/07/06)
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- Direct conversion of phosphonates to phosphine oxides: An improved synthetic route to phosphines including the first synthesis of methyl JohnPhos
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The synthesis of tertiary phosphine oxides from phosphonates was achieved reliably and in good to excellent yields using stoichiometric amounts of alkyl or aryl Grignard reagents and sodium trifluoromethanesulfonate (NaOTf). In the absence of the NaOTf additive, covalent coordination oligomers of magnesium and phosphorus species dominate the reaction, producing very low yields of phosphine oxide, but high conversions of the phosphonate starting material. Mechanistic studies revealed that a five-coordinate phosphorus species - not a phosphinate - is the reaction intermediate. A diverse array of phosphonates was converted to phosphine oxides using a variety of Grignard reagents for direct carbon-phosphorus functionalization. This new methodology especially simplifies the synthesis of dimethylphosphino (RPMe2)-type phosphines by using air-, water-, and silica-stable intermediates. To highlight this reaction, a new Buchwald-type ligand ([1,1′-biphenyl]-2-yldimethylphosphine, or methyl JohnPhos) and a classic bidentate phosphine, bis(diphenylphosphino)propane (dppp), were synthesized in excellent yields.
- Kendall, Alexander J.,Salazar, Chase A.,Martino, Patrick F.,Tyler, David R.
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supporting information
p. 6171 - 6178
(2015/02/19)
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- Cesium carbonate mediated aryl triflate esters' deprotection
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A variety of diversely substituted aryl triflate esters were efficiently deprotected to the parent phenols by exposure to cesium carbonate in toluene. This procedure proved highly compatible with existing functional groups.
- Green, Alice E.,Agouridas, Vangelis,Deniau, Eric
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supporting information
p. 7078 - 7079
(2013/12/04)
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- Efficient indoles and anilines syntheses employing tert-butyl sulfinamide as ammonia surrogate
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tert-Butyl sulfinamide is an ammonia equivalent for the palladium-catalyzed amination of aryl bromides and aryl chlorides. Using these amine derivatives, it has been observed that indoles and anilines with sensitive functional groups can be readily prepared. This surrogate has also been used for the synthesis of indoles from 2-halophenols using palladium catalyzed cross coupling reaction as the key step.
- Prakash, Anjanappa,Dibakar, Mullick,Selvakumar, Kumaravel,Ruckmani, Kandasamy,Sivakumar, Manickam
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supporting information; experimental part
p. 5625 - 5628
(2011/11/06)
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- Synthesis and Application of Chiral Phospholane Ligands Bearing a Sterically and Electrically Adjustable Moiety
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A series of C1-symmetric phosphine-phospholane ligands, 1-(disubstituted phosphino)-2-(phospholano)benzenes (5), which are called UCAPs, with an achiral phosphino group and a chiral phospholane which can be sterically and electrically adjustabl
- Matsumura, Kazuhiko,Shimizu, Hideo,Saito, Takao,Kumobayashi, Hidenori
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p. 180 - 184
(2007/10/03)
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- NOVEL ASYMMETRIC PHOSPHINE LIGAND
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A novel phosphine compound having excellent properties (chemical selectivity, enantioselectivity, catalytic activity) as a catalyst for asymmetric syntheses, especially asymmetric hydrogenation. A phosphine-phosphorane compound represented by the followin
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- Novel asymmetric phosphine ligand
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A phosphine compound having excellent properties (chemical selectivity, enantioselectivity, catalytic activity) as a catalyst for asymmetric syntheses, especially asymmetric hydrogenations. A phosphine-phospholane compound represented by the following for
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- Formation of 1-benzosuberones by three-carbon ring expansion of benzocylobutenones
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A new method for preparing 1-benzosuberone derivatives by free radical promoted three-carbon ring expansion of benzocyclobutenones is described.
- Zhang, Wei,Gorny, Rudiger,Dowd, Paul
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p. 2903 - 2913
(2007/10/03)
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