718628-25-2Relevant academic research and scientific papers
Arylzinc Halides by Silver Catalyzed Zinc Insertion into Aryl Iodides
Casotti, Gianluca,Iuliano, Anna,Carpita, Adriano
, p. 1021 - 1026 (2019)
A catalytic amount of silver acetate efficiently promotes direct insertion of zinc metal into aryl iodides, having different structure, in ethereal solvent. Electron-rich substrates also rapidly undergo oxidative metalation. The arylzinc iodides formed give Negishi coupling products under mild reaction conditions to obtain biaryls in high yields. Sensitive functional groups like aldehydes and primary amides are well-tolerated.
Enantioselective Conjugate Addition of Stabilized Arylzinc Iodide to Enones: an Improved Protocol of the Hayashi Reaction
Casotti, Gianluca,Rositano, Vincenzo,Iuliano, Anna
, p. 1126 - 1131 (2020/12/17)
Stabilised arylzinc iodide, prepared by direct insertion of zinc into aryl iodides, were used as nucleophiles in the Hayashi Rh-catalysed enantioselective conjugate addition to enones. The reaction conditions were optimized in the addition of phenylzinc i
Electrochemical Synthesis of Biaryls via Oxidative Intramolecular Coupling of Tetra(hetero)arylborates
Music, Arif,Baumann, Andreas N.,Spie?, Philipp,Plantefol, Allan,Jagau, Thomas C.,Didier, Dorian
supporting information, p. 4341 - 4348 (2020/03/04)
We report herein versatile, transition metal-free and additive-free (hetero)aryl-aryl coupling reactions promoted by the oxidative electrocoupling of unsymmetrical tetra(hetero)arylborates (TABs) prepared from ligand-exchange reactions on potassium trifluoroarylborates. Exploiting the power of electrochemical oxidations, this method complements the existing organoboron toolbox. We demonstrate the broad scope, scalability, and robustness of this unconventional catalyst-free transformation, leading to functionalized biaryls and ultimately furnishing drug-like small molecules, as well as late stage derivatization of natural compounds. In addition, the observed selectivity of the oxidative coupling reaction is related to the electronic structure of the TABs through quantum-chemical calculations and experimental investigations.
Nickel-Catalyzed α-Carbonylalkylarylation of Vinylarenes: Expedient Access to γ,γ-Diarylcarbonyl and Aryltetralone Derivatives
Dhungana, Roshan K.,Giri, Ramesh,Khanal, Namrata,Shekhar, K. C.
supporting information, p. 8047 - 8051 (2020/04/30)
We report a Ni-catalyzed regioselective α-carbonylalkylarylation of vinylarenes with α-halocarbonyl compounds and arylzinc reagents. The reaction works with primary, secondary, and tertiary α-halocarbonyl molecules, and electronically varied arylzinc reagents. The reaction generates γ,γ-diarylcarbonyl derivatives with α-secondary, tertiary, and quaternary carbon centers. The products can be readily converted to aryltetralones, including a precursor to Zoloft, an antidepressant drug.
Ni-Catalyzed Regioselective β,δ-Diarylation of Unactivated Olefins in Ketimines via Ligand-Enabled Contraction of Transient Nickellacycles: Rapid Access to Remotely Diarylated Ketones
Basnet, Prakash,Dhungana, Roshan K.,Thapa, Surendra,Shrestha, Bijay,Kc, Shekhar,Sears, Jeremiah M.,Giri, Ramesh
, p. 7782 - 7786 (2018/06/22)
We disclose a [(PhO)3P]/NiBr2-catalyzed regioselective β, δ-diarylation of unactivated olefins in ketimines with aryl halides and arylzinc reagents. This diarylation proceeds at remote locations to the carbonyl group to afford, after simple H+ workup, diversely substituted β, δ-diarylketones that are otherwise difficult to access readily with existing methods. Deuterium-labeling and crossover experiments indicate that diarylation proceeds by ligand-enabled contraction of transient nickellacycles.
Ni-Catalyzed Regioselective Alkylarylation of Vinylarenes via C(sp3)-C(sp3)/C(sp3)-C(sp2) Bond Formation and Mechanistic Studies
Kc, Shekhar,Dhungana, Roshan K.,Shrestha, Bijay,Thapa, Surendra,Khanal, Namrata,Basnet, Prakash,Lebrun, Robert W.,Giri, Ramesh
supporting information, p. 9801 - 9805 (2018/08/06)
We report a Ni-catalyzed regioselective alkylarylation of vinylarenes with alkyl halides and arylzinc reagents to generate 1,1-diarylalkanes. The reaction proceeds well with primary, secondary and tertiary alkyl halides, and electronically diverse arylzinc reagents. Mechanistic investigations by radical probes, competition studies and quantitative kinetics reveal that the current reaction proceeds via a Ni(0)/Ni(I)/Ni(II) catalytic cycle by a rate-limiting direct halogen atom abstraction via single electron transfer to alkyl halides by a Ni(0)-catalyst.
Ni-Catalyzed Regioselective Dicarbofunctionalization of Unactivated Olefins by Tandem Cyclization/Cross-Coupling and Application to the Concise Synthesis of Lignan Natural Products
Kc, Shekhar,Basnet, Prakash,Thapa, Surendra,Shrestha, Bijay,Giri, Ramesh
, p. 2920 - 2936 (2018/03/09)
We disclose a (terpy)NiBr2-catalyzed reaction protocol that regioselectively difunctionalizes unactivated olefins with tethered alkyl halides and arylzinc reagents. The reaction shows an excellent functional group tolerance (such as ketones, es
Synergistic Bimetallic Ni/Ag and Ni/Cu Catalysis for Regioselective γ,δ-Diarylation of Alkenyl Ketimines: Addressing β-H Elimination by in Situ Generation of Cationic Ni(II) Catalysts
Basnet, Prakash,Kc, Shekhar,Dhungana, Roshan K.,Shrestha, Bijay,Boyle, Timothy J.,Giri, Ramesh
supporting information, p. 15586 - 15590 (2018/11/23)
We disclose unprecedented synergistic bimetallic Ni/Ag and Ni/Cu catalysts for regioselective γ,δ-diarylation of unactivated alkenes in simple ketimines with aryl halides and arylzinc reagents. The bimetallic synergy, which generates cationic Ni(II) speci
Stereoconvergent arylations and alkenylations of unactivated alkyl electrophiles: Catalytic enantioselective synthesis of secondary sulfonamides and sulfones
Choi, Junwon,Martín-Gago, Pablo,Fu, Gregory C.
supporting information, p. 12161 - 12165 (2014/11/07)
The development of efficient methods for the generation of enantioenriched sulfonamides and sulfones is an important objective for fields such as organic synthesis and medicinal chemistry; however, there have been relatively few reports of direct catalytic asymmetric approaches to controlling the stereochemistry of the sulfur-bearing carbon of such targets. In this report, we describe nickel-catalyzed stereoconvergent Negishi arylations and alkenylations of racemic α-bromosulfonamides and -sulfones that furnish the desired cross-coupling product in very good ee and yield for an array of reaction partners. Mechanistic studies are consistent with the generation of a radical intermediate that has a sufficient lifetime to diffuse out of the solvent cage and to cyclize onto a pendant olefin.
Single-electron-transfer-induced coupling of arylzinc reagents with aryl and alkenyl halides
Shirakawa, Eiji,Tamakuni, Fumiko,Kusano, Eugene,Uchiyama, Nanase,Konagaya, Wataru,Watabe, Ryo,Hayashi, Tamio
supporting information, p. 521 - 525 (2014/01/23)
Arylzinc reagents, prepared from aryl halides/zinc powder or aryl Grignard reagents/zinc chloride, were found to undergo coupling with aryl and alkenyl halides without the aid of transition-metal catalysis to give biaryls and styrene derivatives, respectively. In this context, we have already reported the corresponding reaction using aryl Grignard reagents instead of arylzinc reagents. Compared with the Grignard cross-coupling, the present reaction features high functional-group tolerance, whereby electrophilic groups such as alkoxycarbonyl and cyano groups are compatible as substituents on both the arylzinc reagents and the aryl halides. Aryl halides receive a single electron and thereby become activated as the corresponding anion radicals, which react with arylzinc reagents, thus leading to the cross-coupling products. Arylzinc reagents were found to undergo coupling with aryl and alkenyl halides to give biaryl and styrene derivatives, respectively. The cross-coupling, which features high functional-group tolerance, proceeds through a single-electron-transfer mechanism and thus does not require the aid of transition-metal catalysis.
