3042-69-1Relevant academic research and scientific papers
Manganese-Mediated C?H Alkylation of Unbiased Arenes Using Alkylboronic Acids
Castro, Susana,Fernández, Juan J.,Fa?anás, Francisco J.,Vicente, Rubén,Rodríguez, Félix
, p. 9068 - 9071 (2016)
The alkylation of arenes is an essential synthetic step of interest not only from the academic point of view but also in the bulk chemical industry. Despite its limitations, the Friedel–Crafts reaction is still the method of choice for most of the arene alkylation processes. Thus, the development of new strategies to synthesize alkyl arenes is a highly desirable goal, and herein, we present an alternative method to those conventional reactions. Particularly, a simple protocol for the direct C?H alkylation of unbiased arenes with alkylboronic acids in the presence of Mn(OAc)3?2H2O is reported. Primary or secondary unactivated alkylboronic acids served as alkylating agents for the direct functionalization of representative polyaromatic hydrocarbons (PAHs) or benzene. The results are consistent with a free-radical mechanism.
Reactivity of 1,4-didehydronaphthalene toward organic hydrogen atom donors
Thoen, Kami K.,Thoen, Jason C.,Uckun, Fatih M.
, p. 4019 - 4024 (2000)
1,4-Didehydronaphthalene, generated by thermolysis of 1,2- diethynylbenzene, reacts with organic hydrogen atom donors via hydrogen atom abstraction. The resulting naphthyl radical undergoes the expected abstraction of a hydrogen atom from a second hydrogen atom donor molecule. Surprisingly, significant amounts of radical-radical recombination between the hydrogen donor radical product and the naphthyl radical were also observed for several donors. Further, in some cases, the hydrogen donor radical products also rapidly add to the uncyclized 1,2-diethynylbenzene. (C) 2000 Elsevier Science Ltd.
Cobalt?NHC Catalyzed C(sp2)?C(sp3) and C(sp2)?C(sp2) Kumada Cross-Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents
Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
, p. 202 - 206 (2020/12/01)
The first cobalt-catalyzed cross-coupling of aryl tosylates with alkyl and aryl Grignard reagents is reported. The catalytic system uses CoF3 and NHCs (NHC=N-heterocyclic carbene) as ancillary ligands. The reaction proceeds via highly selective C?O bond functionalization, leading to the corresponding products in up to 98 % yield. The employment of alkyl Grignard reagents allows to achieve a rare C(sp2)?C(sp3) cross-coupling of C?O electrophiles, circumventing isomerization and β-hydride elimination problems. The use of aryl Grignards leads to the formation of biaryls. The C?O cross-coupling sets the stage for a sequential cross-coupling by exploiting the orthogonal selectivity of the catalytic system.
Nickel-catalyzed C-N bond activation: Activated primary amines as alkylating reagents in reductive cross-coupling
Yue, Huifeng,Zhu, Chen,Shen, Li,Geng, Qiuyang,Hock, Katharina J.,Yuan, Tingting,Cavallo, Luigi,Rueping, Magnus
, p. 4430 - 4435 (2019/04/29)
Nickel-catalyzed reductive cross coupling of activated primary amines with aryl halides under mild reaction conditions has been achieved for the first time. Due to the avoidance of stoichiometric organometallic reagents and external bases, the scope regarding both coupling partners is broad. Thus, a wide range of substrates, natural products and drugs with diverse functional groups are tolerated. Moreover, experimental mechanistic investigations and density functional theory (DFT) calculations in combination with wavefunction analysis have been performed to understand the catalytic cycle in more detail.
Visible-Light-Promoted Iron-Catalyzed C(sp2)–C(sp3) Kumada Cross-Coupling in Flow
Wei, Xiao-Jing,Abdiaj, Irini,Sambiagio, Carlo,Li, Chenfei,Zysman-Colman, Eli,Alcázar, Jesús,No?l, Timothy
, p. 13030 - 13034 (2019/07/18)
A continuous-flow, visible-light-promoted method has been developed to overcome the limitations of iron-catalyzed Kumada–Corriu cross-coupling reactions. A variety of strongly electron rich aryl chlorides, previously hardly reactive, could be efficiently coupled with aliphatic Grignard reagents at room temperature in high yields and within a few minutes’ residence time, considerably enhancing the applicability of this iron-catalyzed reaction. The robustness of this protocol was demonstrated on a multigram scale, thus providing the potential for future pharmaceutical application.
Nickel-Catalyzed C(sp2)?C(sp3) Kumada Cross-Coupling of Aryl Tosylates with Alkyl Grignard Reagents
Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
supporting information, p. 2329 - 2336 (2019/04/13)
Aryl tosylates are an attractive class of electrophiles for cross-coupling reactions due to ease of synthesis, low price, and the employment of C?O electrophiles, however, the reactivity of aryl tosylates is low. Herein, we report the Ni-catalyzed C(sp2)?C(sp3) Kumada cross-coupling of aryl tosylates with primary and secondary alkyl Grignard reagents. The method delivers valuable alkyl arenes by cross-coupling with challenging alkyl organometallics possessing β-hydrogens that are prone to β-hydride elimination and homo-coupling. The reaction is catalyzed by an air- and moisture stable-Ni(II) precatalyst. A broad range of electronically-varied aryl tosylates, including bis-tosylates, underwent this transformation, and many examples are suitable at mild room temperature conditions. The combination of Ar?X cross-coupling with the facile Ar?OH activation/cross-coupling strategy permits for orthogonal cross-coupling with challenging alkyl organometallics. Furthermore, we demonstrate that the method operates with TON reaching 2000, which is one of the highest turnovers observed to date in Ni-catalyzed cross-couplings. (Figure presented.).
Iron-Catalyzed C(sp2)–C(sp3) Cross-Coupling of Alkyl Grignard Reagents with Polyaromatic Tosylates
Piontek, Aleksandra,Szostak, Michal
, p. 7271 - 7276 (2018/01/02)
The iron-catalyzed cross-coupling of polyaromatic tosylates with alkyl Grignard reagents controlled by O-coordinating ligand is reported. The reaction operates under very mild, operationally practical conditions to furnish alkylated polyaromatics that are a common motif in a wide range of electronic-material, pharmaceutical and high-performance fluid applications. The challenging C(sp2)–C(sp3) cross-coupling products are obtained in good to excellent yields obviating the problems associated with β-hydride elimination. For the first time the coupling of polyaromatic tosylates can be achieved in the presence of sensitive carboxylic acid derived functional groups. Mechanistic studies suggest that the reaction selectivity can be correlated with the reduction potential of polyaromatic hydrocarbons. The method represents a rare example of sustainable C–O bond alkylation of polyarenes at room temperature.
Ionic iron(III) complexes bearing a dialkylbenzimidazolium cation: Efficient catalysts for magnesium-mediated cross-couplings of aryl phosphates with alkyl bromides
Li, Zhuang,Lu, Bing,Sun, Hongmei,Shen, Qi,Zhang, Yong
, (2017/07/24)
A series of ionic iron(III) complexes of general formula [HLn][FeX4] (HL1?=?1,3-dibenzylbenzimidazolium cation, X?=?Cl, 1; HL1, X?=?Br, 2; HL2?=?1,3-dibutylbenzimidazolium cation, X?=?Br, 3; HL3?=?1,3-bis(diphenylmethyl)benzimidazolium cation, X?=?Br, 4) were easily prepared in high yields by the direct reaction of FeX3 with 1 equiv. of [HLn]X under mild conditions. All of them were characterized using elemental analysis, Raman spectroscopy and electrospray ionization mass spectrometry, and X-ray crystallography for 1 and 4. In the presence of magnesium turnings and LiCl, these air- and moisture-insensitive complexes showed high catalytic activities in direct cross-couplings of aryl phosphates with primary and secondary alkyl bromides with broad substrate scope, wherein complex 4 was the most effective.
Alkyl?(Hetero)Aryl Bond Formation via Decarboxylative Cross-Coupling: A Systematic Analysis
Sandfort, Frederik,O'Neill, Matthew J.,Cornella, Josep,Wimmer, Laurin,Baran, Phil S.
supporting information, p. 3319 - 3323 (2017/03/17)
Suzuki, Negishi, and Kumada couplings are some of the most important reactions for the formation of skeletal C?C linkages. Their widespread use to forge bonds between two aromatic rings has enabled every branch of chemical science. The analogous union between alkyl halides and metallated aryl systems has not been as widely employed due to the lack of commercially available halide building blocks. Redox-active esters have recently emerged as useful surrogates for alkyl halides in cross-coupling chemistry. Such esters are easily accessible through reactions between ubiquitous carboxylic acids and coupling agents widely used in amide bond formation. This article features an amalgamation of in-house experience bolstered by approximately 200 systematically designed experiments to accelerate the selection of ideal reaction conditions and activating agents for the cross-coupling of primary, secondary, and tertiary alkyl carboxylic acids with both aryl and heteroaryl organometallic species.
Ionic iron (II) composition as well as preparation method and application thereof
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Paragraph 0048, (2017/01/02)
The invention discloses an ionic iron (II) composition as well as a preparation method and application thereof. The ionic iron (II) composition contains phosphine ligands and imidazole (quinoline) cations, and the general formula of the ionic iron (II) is [Fe(PR3)X3][(R1NCHnCHnNR1)CH], wherein X is selected from one of chlorine or bromine. The ionic iron (II) composition containing the phosphine ligands and the imidazole (quinoline) cations can efficiently catalyze a phosphoric acid aryl diethyl ester compound and an alkyl group Grignard reagent to perform a crisscross coupling reaction, and particularly can effectively catalyze an unactivated phosphoric acid aryl diethyl ester compound and the alkyl group Grignard reagent to perform the reaction.
