1009-43-4Relevant articles and documents
Design, Synthesis, and Implementation of Sodium Silylsilanolates as Silyl Transfer Reagents
Yamagishi, Hiroki,Saito, Hayate,Shimokawa, Jun,Yorimitsu, Hideki
, p. 10095 - 10103 (2021)
There is an increasing demand for facile delivery of silyl groups onto organic bioactive molecules. One of the common methods of silylation via a transition-metal-catalyzed coupling reaction employs hydrosilane, disilane, and silylborane as major silicon sources. However, the labile nature of the reagents or harsh reaction conditions sometimes render them inadequate for the purpose. Thus, a more versatile alternative source of silyl groups has been desired. We hereby report a design, synthesis, and implementation of storable sodium silylsilanolates that can be used for the silylation of aryl halides and pseudohalides in the presence of a palladium catalyst. The developed method allows a late-stage functionalization of polyfunctionalized compounds with a variety of silyl groups. Mechanistic studies indicate that (1) a nucleophilic silanolate attacks a palladium center to afford a silylsilanolate-coordinated arylpalladium intermediate and (2) a polymeric cluster of silanolate species assists in the intramolecular migration of silyl groups, which would promote an efficient transmetalation.
Functionalized styrene synthesis via palladium-catalyzed C[sbnd]C cleavage of aryl ketones
Zhang, Xu,Wang, Zhen-Yu,Wang, Xing,Xu, Hui,Dai, Hui-Xiong
, (2022/03/31)
We report herein the synthesis of functionalized styrenes via palladium-catalyzed Suzuki–Miyaura cross-coupling reaction between aryl ketone derivatives and potassium vinyltrifluoroborate. The employment of pyridine-oxazoline ligand was the key to the cleavage of unstrained C[sbnd]C bond. A variety of functional groups and biologically important moleculars were well tolerated. The orthogonal Suzuki–Miyaura coupling demonstrated the synthetic practicability.
Nickel-Catalyzed Reductive Cross-Coupling of Aryl Bromides with Vinyl Acetate in Dimethyl Isosorbide as a Sustainable Solvent
Su, Mincong,Huang, Xia,Lei, Chuanhu,Jin, Jian
supporting information, p. 354 - 358 (2022/01/15)
A nickel-catalyzed reductive cross-coupling has been achieved using (hetero)aryl bromides and vinyl acetate as the coupling partners. This mild, applicable method provides a reliable access to a variety of vinyl arenes, heteroarenes, and benzoheterocycles, which should expand the chemical space of precursors to fine chemicals and polymers. Importantly, a sustainable solvent, dimethyl isosorbide, is used, making this protocol more attractive from the point of view of green chemistry.
Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
Dong, Guangbin,Xu, Yan,Zhou, Xukai
supporting information, p. 20042 - 20048 (2021/12/03)
The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
An Electroreductive Approach to Radical Silylation via the Activation of Strong Si-Cl Bond
Lu, Lingxiang,Siu, Juno C.,Lai, Yihuan,Lin, Song
supporting information, p. 21272 - 21278 (2020/12/21)
The construction of C(sp3)-Si bonds is important in synthetic, medicinal, and materials chemistry. In this context, reactions mediated by silyl radicals have become increasingly attractive but methods for accessing these intermediates remain limited. We present a new strategy for silyl radical generation via electroreduction of readily available chlorosilanes. At highly biased potentials, electrochemistry grants access to silyl radicals through energetically uphill reductive cleavage of strong Si-Cl bonds. This strategy proved to be general in various alkene silylation reactions including disilylation, hydrosilylation, and allylic silylation under simple and transition-metal-free conditions.
Palladium-Catalyzed Mizoroki-Heck Reaction of Nitroarenes and Styrene Derivatives
Okita, Toshimasa,Asahara, Kitty K.,Muto, Kei,Yamaguchi, Junichiro
supporting information, p. 3205 - 3208 (2020/04/10)
We have developed a Mizoroki-Heck reaction of nitroarenes with alkenes under palladium catalysis. The use of a Pd/BrettPhos catalyst promoted the alkenylation, whereas other catalysts led to a decrease in the product yield. In addition to nitroarenes, nitroheteroarenes were also applicable to the present reaction. The combination of a nucleophilic aromatic substitution (SNAr) with the denitrative alkenylation produced a multifunctionalized arene in a one-pot operation.
Why is cis/trans stereoinversion with Li+(THF)4 migration across the phenyl ring of α-lithiostyrene accelerated by two ortho-methyl groups?
Knorr, Rudolf,Lattke, Ernst,Ruhdorfer, Jakob,Ferchland, Kathrin,von Roman, Ulrich
, p. 1621 - 1631 (2018/02/28)
Common wisdom might anticipate that two methyl groups placed on a molecular migration route should act as an impediment. However, the “conducted tour” migration of Li+(THF)4 across the aryl ring (“π-route”) during the cis/trans stereoinversion of α-arylvinyllithiums had been found to occur with practically equal velocities in the presence of either one or two ortho-alkyl substituents. We now report that the omission of both ortho-methyl groups retards the stereoinversion process. In order to arrive at an answer to the title question, we investigate the aggregation equilibria and microsolvation states of ortho, ortho′-unsubstituted α-lithiostyrenes by means of approved secondary NMR criteria. Beyond such necessary knowledge about the ground-state properties, we provide kinetic evidence showing that the retarded cis/trans stereoinversion of α-lithiostyrene proceeds by the pseudomonomolecular, ionic mechanism with Li+(THF)4 migration.
Iridium-Catalyzed α-Selective Arylation of Styrenes by Dual C?H Functionalization
Cooper, Phillippa,Crisenza, Giacomo E. M.,Feron, Lyman J.,Bower, John F.
supporting information, p. 14198 - 14202 (2018/10/02)
An IrI-system modified with a ferrocene derived bisphosphine ligand promotes α-selective arylation of styrenes by dual C?H functionalization. These studies offer a regioisomeric alternative to the Pd-catalyzed Fujiwara–Moritani reaction.
General access to para-substituted styrenes
Langle, Sandrine,David-Quillot, Franck,Balland, Alexia,Abarbri, Mohamed,Duchêne, Alain
, p. 113 - 119 (2007/10/03)
A simple and efficient procedure has been developed for the synthesis of organogermanium compounds and styrenes para-substituted with groups containing an atom of the 14th group by one-pot reaction of halogenosilanes, germanes or stannanes, organic halides and magnesium using ultrasound methods.
General access to para-substituted styrenes
Langle, Sandrine,David-Quillot, Franck,Balland, Alexia,Abarbri, Mohamed,Duchêne, Alain
, p. 113 - 119 (2015/03/05)
A simple and efficient procedure has been developed for the synthesis of organogermanium compounds and styrenes para-substituted with groups containing an atom of the 14th group by one-pot reaction of halogenosilanes, germanes or stannanes, organic halides and magnesium using ultrasound methods.
