46346-12-7Relevant academic research and scientific papers
Mechanistic studies of ruthenium-catalyzed anti-Markovnikov hydroamination of vinylarenes: Intermediates and evidence for catalysis through π-arene complexes
Takaya, Jun,Hartwig, John F.
, p. 5756 - 5757 (2005)
Studies are described that reveal the steps of the anti-Markovnikov hydroamination of vinylarenes with alkylamines catalyzed by Ru(COD)(2-methylallyl)2, bis(diphenylphosphino)pentane, and TfOH. Treatment of the catalyst components with an exces
A potassium magnesiate complex: Synthesis, structure and catalytic intermolecular hydroamination of styrenes
Guan, Bing-Tao,Liu, Yu-Feng,Zhai, Dan-Dan,Zhang, Xiang-Yu
supporting information, (2022/01/19)
A new heterobimetallic potassium magnesiate complex KMg[N(SiMe3)2]2Bn (Bn = PhCH2-) was synthesized by simply mixing magnesium amide and potassium benzyl in toluene. The TMEDA-ligated potassium magnesiate comple
Photo-induced thiolate catalytic activation of inert Caryl-hetero bonds for radical borylation
K?nig, Burkhard,Wang, Hua,Wang, Shun
supporting information, p. 1653 - 1665 (2021/06/17)
Substantial effort is currently being devoted to obtaining photoredox catalysts with high redox power. Yet, it remains challenging to apply the currently established methods to the activation of bonds with high bond dissociation energy and to substrates with high reduction potentials. Herein, we introduce a novel photocatalytic strategy for the activation of inert substituted arenes for aryl borylation by using thiolate as a catalyst. This catalytic system exhibits strong reducing ability and engages non-activated Caryl–F, Caryl–X, Caryl–O, Caryl–N, and Caryl–S bonds in productive radical borylation reactions, thus expanding the available aryl radical precursor scope. Despite its high reducing power, the method has a broad substrate scope and good functional-group tolerance. Spectroscopic investigations and control experiments suggest the formation of a charge-transfer complex as the key step to activate the substrates.
B(C6F5)3-catalyzed tandem protonation/deuteration and reduction of: In situ -formed enamines
Wu, Rongpei,Gao, Ke
, p. 4032 - 4036 (2021/05/19)
A highly efficient B(C6F5)3-catalyzed tandem protonation/deuteration and reduction of in situ-formed enamines in the presence of water and pinacolborane was developed. Regioselective β-deuteration of tertiary amines was achieved with high chemo- and regioselectivity. D2O was used as a readily available and cheap source of deuterium. Mechanistic studies indicated that B(C6F5)3 could activate water to promote the protonation and reduction of enamines. This journal is
Synthesis of Arylethylamines via C(sp3)-C(sp3) Palladium-Catalyzed Cross-Coupling
Lippa, Rhys A.,Battersby, David J.,Murphy, John A.,Barrett, Tim N.
, p. 3583 - 3604 (2021/02/27)
Substituted arylethylamines represent a key structural motif in natural, pharmaceutical, and agrochemical compounds. Access to such scaffolds has been the subject of long-standing synthetic interest. Herein, we report the synthesis of such scaffolds via a palladium-catalyzed C(sp3)-C(sp3) coupling between (chloromethyl)aryls and air-/moisture-stable N,N-dialkylaminomethyltrifluoroborate salts. Rapid hit identification was achieved using microscale high-throughput experimentation and was followed by millimolar-scale reaction parameter optimization. A range of structurally and electronically varied arylethylamine products were obtained in moderate to excellent yields (27-96%, >60 examples). The reaction mechanism is proposed to proceed via formation of a trialkylbenzylammonium species prior to oxidative addition.
Ambient Moisture Accelerates Hydroamination Reactions of Vinylarenes with Alkali-Metal Amides under Air
Bole, Leonie J.,Davin, Laia,García-álvarez, Joaquín,Hernán-Gómez, Alberto,Hevia, Eva,Kennedy, Alan,Mulks, Florian F.
supporting information, p. 19021 - 19026 (2020/09/01)
A straightforward alkali-metal-mediated hydroamination of styrenes using biorenewable 2-methyltetrahydrofuran as a solvent is reported. Refuting the conventional wisdom of the incompatibility of organolithium reagents with air and moisture, shown here is that the presence of moisture is key in favoring formation of the target phenethylamines over competing olefin polymerization products. The method is also compatible with sodium amides, with the latter showing excellent promise as highly efficient catalysts under inert atmosphere conditions.
Alkali metal and stoichiometric effects in intermolecular hydroamination catalysed by lithium, sodium and potassium magnesiates
Davin, Laia,Hernán-Gómez, Alberto,McLaughlin, Calum,Kennedy, Alan R.,McLellan, Ross,Hevia, Eva
, p. 8122 - 8130 (2019/06/18)
Main group bimetallic complexes, while being increasingly used in stoichiometric deprotonation and metal-halogen exchange reactions, have not yet made a significant impact in catalytic applications. This paper explores the ability of alkali metal magnesiates to catalyse the intermolecular hydroamination of alkynes and alkenes using sytrene and diphenylacetylene as principle setting model substrates. By systematically studying the role of the alkali-metal and the formulation of the heterobimetallic precatalyst, this study establishes higher order potassium magnesiate [(PMDETA)2K2Mg(CH2SiMe3)4] (7) as a highly effective system capable of catalysing hydroamination of styrene and diphenylacetylene with several amines while operating at room temperature. This high reactivity contrasts with the complete lack of catalytic ability of neutral Mg(CH2SiMe3)2, even when harsher reaction conditions are employed (24 h, 80 °C). A pronounced alkali metal effect is also uncovered proving that the alkali metal (Li, Na, or K) is not a mere spectating counterion. Through stoichiometric reactions, and structural and spectroscopic (DOSY NMR) investigations we shed some light on the potential reaction pathway as well as the constitution of key intermediates. This work suggests that the enhanced catalytic activity of 7 can be rationalised in terms of the superior nucleophilic power of the formally dianionic magnesiate {Mg(NR2)4}2- generated in situ during the hydroamination process, along with the ability of potassium to engage in π-interactions with the unsaturated organic substrate, enhancing its susceptibility towards a nucleophilic attack by the amide anion.
Cyclometalated palladium pre-catalyst for N-alkylation of amines using alcohols and regioselective alkylation of sulfanilamide using aryl alcohols
Mamidala, Ramesh,Mukundam, Vanga,Dhanunjayarao, Kunchala,Venkatasubbaiah, Krishnan
supporting information, p. 2225 - 2233 (2017/03/24)
Simple pyrazole based palladacycle-phosphine with a high turnover has been developed and applied for the N-alkylation of amines and sulfanilamide using alcohols as substrates by hydrogen borrowing strategy. N-alkylation of primary and secondary amines resulted in high isolated yields at 100–130 °C, under solvent free conditions. More challenging secondary aliphatic as well as aromatic alcohols were also successfully utilized as alkylating agents under similar reaction conditions. The turn over number reached up to 43000 for N-benzylation of aniline using benzyl alcohol. Notably, regioselective N-alkylation of 2-aminobenzothiazole and 4-aminobenzenesulfonamide to the corresponding 2-N-(alkylamino)azoles and 4-amino-(N-alkyl)benzenesulfonamides using alcohols as alkylating agents have been achieved using our new pre-catalyst-phosphine system.
Lithium-Catalyzed anti-Markovnikov Intermolecular Hydroamination Reactions of Vinylarenes and Simple Secondary Amines
Germain, Stéphane,Lecoq, Meije,Schulz, Emmanuelle,Hannedouche, Jér?me
, p. 1749 - 1753 (2017/05/26)
Various β-arylethylamine derivatives were straightforwardly obtained by the lithium-catalyzed anti-Markovnikov selective intermolecular hydroamination reaction of secondary aliphatic amines with vinylarenes. The use of only 1.5 mol % LiCH2TMS as a solid base in THF proved to be efficient to deliver the target products at room temperature with up to complete conversions. Both reaction partners were, moreover, used in equivalent amounts; thus, this protocol best respects the concepts of sustainable chemistry for the easy preparation of lead structures for pharmaceutically active compounds.
SmI2(H2O)n Reduction of Electron Rich Enamines by Proton-Coupled Electron Transfer
Kolmar, Scott S.,Mayer, James M.
supporting information, p. 10687 - 10692 (2017/08/15)
Samarium diiodide in the presence of water and THF (SmI2(H2O)n) has in recent years become a versatile and useful reagent, mainly for reducing carbonyl-type substrates. This work reports the reduction of several enamines by SmI2(H2O)n. Mechanistic experiments implicate a concerted proton-coupled electron transfer (PCET) pathway, based on various pieces of evidence against initial outer-sphere electron transfer, proton transfer, or substrate coordination. A thermochemical analysis indicates that the C-H bond formed in the rate-determining step has a bond dissociation free energy (BDFE) of ～32 kcal mol-1. The O-H BDFE of the samarium aquo ion is estimated to be 26 kcal mol-1, which is among the weakest known X-H bonds of stable reagents. Thus, SmI2(H2O)n should be able to form very weak C-H bonds. The reduction of these highly electron rich substrates by SmI2(H2O)n shows that this reagent is a very strong hydrogen atom donor as well as an outer-sphere reductant.
