- Ni-Catalyzed Cross-Electrophile Coupling of Aryl Triflates with Thiocarbonates via C-O/C-O Bond Cleavage
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A nickel-catalyzed reductive coupling of aryl triflates with thiocarbonates is reported here. Both electron-rich and -deficient aryl C(sp2)-O electrophiles as well as a class of O-tBu S-alkyl thiocarbonates are compatible with the optimized reaction conditions, as evidenced by 49 examples. The reaction also proceeds with good chemoselective cleavage of the C-O bond with regard to thioesters. This work broadens the scope of nickel-catalyzed reductive cross-electrophile coupling reactions.
- Zhu, Zhaodong,Gong, Yuxin,Tong, Weiqi,Xue, Weichao,Gong, Hegui
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supporting information
p. 2158 - 2163
(2021/04/05)
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- Palladium-Catalyzed Reductive Carbonylation of (Hetero) Aryl Halides and Triflates Using Cobalt Carbonyl as CO Source
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An efficient protocol for the reductive carbonylation of (hetero) aryl halides and triflates under CO gas-free conditions using Pd/Co2(CO)8 and triethylsilane has been developed. The mild reaction conditions, enhanced chemoselectivity and, easy access to heterocyclic and vinyl carboxaldehydes highlights its importance in organic synthesis.
- Dogga, Bhushanarao,Joseph, Jayan T.,Kumar, C. S. Ananda
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supporting information
p. 309 - 313
(2020/12/23)
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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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- The Directed ortho Metalation (D o M)-Cross-Coupling Connection: Synthesis of Polyfunctional Biaryls
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A comparative evaluation of the combined directed ortho metalation (D o M)-Suzuki-Miyaura and D o M-Negishi cross-coupling reactions with aryl triflates for the synthesis of substituted biaryls is described. Both ortho -zinc and ortho -boron aryl directed
- Quesnelle, Claude A.,Snieckus, Victor
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supporting information
p. 4413 - 4428
(2018/11/21)
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- Palladium nanoparticles: Chemoselective control for reductive Heck with aryl triflates and 2,3-dihydrofuran
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The reductive-Heck reaction offers a unique entry to formal Csp2-Csp3 cross-coupling reactions that proceed in the absence of a main group organometallic coupling partner. Consequently, further development of new variants would be transformative. Unfortunately, controlling the relative rates of the organopalladium intermediates has proven difficult with homogenous, single-site Pd catalysts. This work describes a selective reductive Heck reaction catalyzed by Pd-nanoparticles. The reaction works well with electron-deficient aryl triflates at room temperature in the absence of ligands. This work addresses some of the challenges found in the reductive-Heck literature.
- Rosas Vargas, Daisy,Cook, Silas P.
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supporting information
p. 3314 - 3317
(2018/05/04)
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- Efficient cross-coupling of aryl/alkenyl triflates with acyclic secondary alkylboronic acids
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Aryl-secondary alkyl cross-coupling with aryl sulfonate esters as coupling partners remains a significant challenge. Efficient cross-coupling between aryl/alkenyl triflates and acyclic secondary alkylboronic acids is realized for the first time to provide a series of sterically congested acyclic secondary alkyl arenes/olefins in good to excellent yields. The employment of sterically bulky P,PO ligand L1/L2 is crucial for the high yields and selectivities. The method has enabled a concise and 4-step synthesis of a key intermediate of male contraceptive agent and PAF antagonist gossypol.
- Si, Tengda,Li, Bowen,Xiong, Wenrui,Xu, Bin,Tang, Wenjun
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supporting information
p. 9903 - 9909
(2017/12/12)
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- Highly activated vinyl hydrogen in a significantly twisted styrene
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(Chemical Equation Presented) The novel example of a vinylic hydrogen more reactive than a benzylic hydrogen was found by treatment of a twisted styrene derivative with a strong base followed by D2O quenching. In this paper, the full details of
- Mori, Hajime,Matsuo, Takafumi,Yoshioka, Yasunori,Katsumura, Shigeo
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p. 9004 - 9012
(2007/10/03)
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- Preparation and Palladium-Catalyzed Cross-Coupling of Aryl Triethylammonium Bis(catechol) Silicates with Aryl Triflates
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Pentavalent aryl and heteroaryl bis(catechol) silicates undergo palladium-catalyzed cross-coupling with aryl and heteroaryl triflates in the presence of a fluoride source in excellent yields. These solid, air-stable bis(catechol) silicates are prepared from a high-yielding displacement reaction between catechol and an aryl siloxane in the presence of an amine base. The cross-coupling reaction is tolerant of a wide range of electron-donating and electron-withdrawing groups. Several examples of di-ortho-substituted triflates are successfully coupled with these reagents.
- Seganish, W. Michael,DeShong, Philip
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p. 1137 - 1143
(2007/10/03)
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- Process for the preparation of secondary amines
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N,N-disubstituted amines in which the amino nitrogen atom is bound to the carbon atom of an aromatic ring disubstituted in the positions ortho to the carbon atom, are prepared by allowing a primary amine and a compound in which an ortho, ortho-disubstituted aromatic compound carrying a nucleofuge substituent, to react in a basic environment in the presence of a catalytic palladium(0) complex and a ligand, the ratio of palladium complex to ligand being greater than at least 1:1. A typical embodiment involves the reaction of 2-methyl-6-ethylphenyl-trifluoromethylsulfonate and (S)-1-methoxy-2-aminopropane in the presence of bis(dibenzylideneacetone)palladium, tri-tert.-butylphosphine, and sodium tert.-butoxide to yield (S)-N-(1-methoxyprop-2-yl)-2-methyl-6-ethylphenylamine.
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- A high throughput synthesis of aryl triflate and aryl nonaflate promoted by a polymer supported base (PTBD)
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A rapid synthesis of aryl triflate and aryl nonaflate was developed using 4-nitrophenyl triflate and 4-nitrophenyl nonaflate as perfluoroalkanesulfonyl transfer reagents in combination with a polymer supported base (PTBD). Simple filtration of the reactio
- Boisnard, Sabine,Chastanet, Jaqueline,Zhu, Jieping
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p. 7469 - 7472
(2007/10/03)
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- Palladium-Catalyzed Cross-Coupling Reactions of Highly Hindered, Electron-Rich Phenol Triflates and Organostannanes
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The palladium-catalyzed cross-coupling reaction of highly hindered, electron-rich phenol triflates and organostannanes (Stille reaction) has been studied in a systematic manner.The following are its salient features: (1) electron-rich phenol triflates require triphenylphosphine to undergo palladium-catalyzed cross-couplings; (2) in general, efficient reactions take place only when larger-than-usual amounts (10-15percent) of palladium are employed.On the reagent side, alkyl- (methyl only), allyl-, vinyl- and alkinylstannanes undergo efficient cross-couplings with the titlesubstrates.However, some limitations to this novel entry to 2-substituted resorcinols exist in regard to both substrates and reagents.Thus, conformationally rigid (hexasubstituted) aryl triflates behave poorly, demethylation being an important side reaction.Moreover, alkyl groups other than methyl cannot be introduced because β elimination occurs more rapidly.The potentially powerful synthesis of hindered biaryls has also been studied briefly.In the present conditions, the reaction appears to be limited by the presence of ortho substituents on the arylstannane moiety.
- Saa, Jose M.,Martorell, Gabriel,Garcia-Raso, Angel
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p. 678 - 685
(2007/10/02)
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- Palladium Catalysed Alkoxycarbonylation of Phenols to Benzoate Esters
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The methoxycarbonylation of aryl trifluoromethanesulphonates with CO and aliphatic alcohols is catalysed by Pd(OAc)2-1,3-bis(diphenylphosphino)propane in high yield at 70 deg C and ambient CO pressure.
- Dolle, Roland E.,Schmidt, Stanley J.,Kruse, Lawrence I.
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p. 904 - 905
(2007/10/02)
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- Reaction of Triflates with Potassium Diethyl Phosphite. Formation of Phosphate Esters
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Phenyl triflate and substituted analogues react with potassium diethyl phosphite in liquid ammonia to form aryl diethyl phosphate esters.The reaction formally involves loss of trifluoromethanesulfinate ion from the triflate and concomitant oxidation of phosphorus to the phosphate stage.Preliminary data suggest that, in a series of triflates, reactivity follows the order aryl > cyclohexenyl > cyclopropyl > alkyl.Studies on aryl triflates with added labeled phenoxide rule out a mechanism involving free phenoxide ion, i.e., displacement of phenoxide by nucleophilic attack of diethyl phosphite ion on sulfur followed by phosphorylation of displaced phenoxide.Three potential mechanisms, including one involving initial attack of phosphorus at sulfur, a biphilic insertion mechanism, and one involving nucleophilic attack on oxygen, are suggested, all of which could account for these observations.
- Creary, Xavier,Benage, Brigitte,Hilton, Kathryn
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p. 2887 - 2891
(2007/10/02)
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