60492-48-0Relevant academic research and scientific papers
Nickel-Catalyzed Enantioselective Hydroboration of Vinylarenes
Tran, Hai N.,Stanley, Levi M.
supporting information, p. 395 - 399 (2021/12/27)
The enantioselective hydroboration of vinylarenes catalyzed by a chiral, nonracemic nickel catalyst is presented as a facile method for generating chiral benzylic boronate esters. Various vinylarenes react with bis(pinacolato)diboron (B2pin2) in the presence of MeOH as a hydride source to form chiral boronate esters in up to 92% yield with up to 94% ee. The use of anhydrous Me4NF to activate B2pin2 is crucial for ensuring fast transmetalation to achieve high enantioselectivities.
A Cobalt-Catalyzed Enantioconvergent Radical Negishi C(sp3)-C(sp2) Cross-Coupling with Chiral MultidentateN,N,P-Ligand
Li, Zhuang,Cheng, Xian-Yan,Yang, Ning-Yuan,Chen, Ji-Jun,Tang, Wen-Yue,Bian, Jun-Qian,Cheng, Yong-Feng,Li, Zhong-Liang,Gu, Qiang-Shuai,Liu, Xin-Yuan
supporting information, p. 2215 - 2219 (2021/05/29)
A cobalt-catalyzed enantioconvergent radical Negishi C(sp3)-C(sp2) cross-coupling of racemic benzyl chlorides with arylzinc reagents has been developed in good yield with moderate enantioselectivities. This strategy provides an expedient access toward a range of enantioenriched 1,1-diarylmethanes. Key to this discovery is the utilization of a chiral multidentate anionicN,N,P-ligand to strongly coordinate with the cobalt catalyst and tune its chiral environment, thus achieving the enantiocontrol over the highly reactive prochiral alkyl radical species.
Chiral Iridium Complexes of Anionic NCP Pincer Ligand for Asymmetric Transfer Hydrogenation of 1,1-Diarylethenes with Ethanol
Qian, Lu,Tang, Xixia,Huang, Zhidao,Wang, Yulei,Liu, Guixia,Huang, Zheng
supporting information, p. 8978 - 8983 (2021/11/24)
Chiral iridium complexes ligated by anionic oxazoline-bearing NCP-type pincer ligands were developed and applied to the asymmetric transfer hydrogenation (ATH) of diarylethenes using environmentally benign ethanol as the hydrogen donor. High enantioselectivities could be achieved for substrates bearing ortho-Me, ortho-Cl, or ortho-Br substituents on one of the aryl groups. The ATH of ortho-Br-substituted diarylethenes is particularly attractive due to the propensity of the C(aryl)-Br bond to undergo various new bond-forming events.
Reactivity of (bi-Oxazoline)organonickel Complexes and Revision of a Catalytic Mechanism
Ju, Luchuan,Lin, Qiao,LiBretto, Nicole J.,Wagner, Clifton L.,Hu, Chunhua Tony,Miller, Jeffrey T.,Diao, Tianning
supporting information, p. 14458 - 14463 (2021/09/18)
Bi-Oxazoline (biOx) has emerged as an effective ligand framework for promoting nickel-catalyzed cross-coupling, cross-electrophile coupling, and photoredox-nickel dual catalytic reactions. This report fills the knowledge gap of the organometallic reactivity of (biOx)Ni complexes, including catalyst reduction, oxidative electrophile activation, radical capture, and reductive elimination. The biOx ligand displays no redox activity in (biOx)Ni(I) complexes, in contrast to other chelating imine and oxazoline ligands. The lack of ligand redox activity results in more negative reduction potentials of (biOx)Ni(II) complexes and accounts for the inability of zinc and manganese to reduce (biOx)Ni(II) species. On the basis of these results, we revise the formerly proposed “sequential reduction” mechanism of a (biOx)Ni-catalyzed cross-electrophile coupling reaction by excluding catalyst reduction steps.
Nickel-Catalyzed Regiodivergent Reductive Hydroarylation of Styrenes
Xue, Yuhang,Chen, Jian,Song, Peihong,He, Yuli,Zhu, Shaolin
, p. 1647 - 1651 (2021/07/02)
We report a ligand-controlled nickel-catalyzed reductive hydroarylation of styrenes with predictable and controllable regioselectivity. With a diamine ligand, the reaction produces selective linear hydroarylation products. Alternatively, with a chiral PyrOx ligand, branch-selective enantioenriched 1,1-diarylalkane products are obtained. Preliminary mechanistic results are consistent with a reductive Heck process.
Nickel-Catalyzed Asymmetric Hydroarylation of Vinylarenes: Direct Enantioselective Synthesis of Chiral 1,1-Diarylethanes
Tran, Hai N.,Burgett, Russell W.,Stanley, Levi M.
, p. 3836 - 3849 (2021/03/01)
The enantioselective hydroarylation of vinylarenes catalyzed by a chiral, non-racemic nickel catalyst is presented as a facile method to generate chiral 1,1-diarylethanes. These reactions proceed via formation of a chiral, non-racemic nickel benzyl intermediate. Transmetalation with arylboron nucleophiles and subsequent reductive elimination enable the formation of a variety of chiral 1,1-diarylethanes. The 1,1-diarylethane products from reactions of arylboronic acids containing electron-donating substituents are formed with typically greater than 90% ee, while the 1,1-diarylethanes generated from reactions of arylboronic acids containing electron-withdrawing groups are generated with typically less than 80% ee. These results are consistent with the rate of transmetalation with an arylboron nucleophile playing a key role in the enantioselectivity of these hydroarylation reactions. This mechanistic insight has led to the development of reactions of neo-pentylglycolate esters of arylboronic acids with vinylarenes that occur with higher enantioselectivities based on increased rates of transmetalation.
Iron-catalysed enantioconvergent Suzuki-Miyaura cross-coupling to afford enantioenriched 1,1-diarylalkanes
Tyrol, Chet C.,Yone, Nang S.,Gallin, Connor F.,Byers, Jeffery A.
supporting information, p. 14661 - 14664 (2020/12/02)
The first stereoconvergent Suzuki-Miyaura cross-coupling reaction was developed to afford enantioenriched 1,1-diarylalkanes. An iron-based complex containing a chiral cyanobis(oxazoline) ligand framework was best to obtain enantioenriched 1,1-diarylalkanes from cross-coupling reactions between unactivated aryl boronic esters and benzylic chlorides. Enhanced yields were obtained when 1,3,5-trimethoxybenzene was used as an additive, which is hypothesized to extend the lifetime of the iron-based catalyst. Exceptional enantioselectivities were obtained with challenging ortho-substituted benzylic chlorides. This journal is
Copper-Catalyzed Enantioconvergent Radical Suzuki-Miyaura C(sp3)-C(sp2) Cross-Coupling
Jiang, Sheng-Peng,Dong, Xiao-Yang,Gu, Qiang-Shuai,Ye, Liu,Li, Zhong-Liang,Liu, Xin-Yuan
supporting information, p. 19652 - 19659 (2020/12/01)
A copper-catalyzed enantioconvergent Suzuki-Miyaura C(sp3)-C(sp2) cross-coupling of various racemic alkyl halides with organoboronate esters has been established in high enantioselectivity. Critical to the success is the use of a chiral cinchona alkaloid-derived N,N,P-ligand for not only enhancing the reducing capability of copper catalyst to favor a stereoablative radical pathway over a stereospecific SN2-type process but also providing an ideal chiral environment to achieve the challenging enantiocontrol over the highly reactive radical species. The reaction has a broad scope with respect to both coupling partners, covering aryl- and heteroarylboronate esters, as well as benzyl-, heterobenzyl-, and propargyl bromides and chlorides with good functional group compatibility. Thus, it provides expedient access toward a range of useful enantioenriched skeletons featuring chiral tertiary benzylic stereocenters.
Nickel-catalyzed Enantioselective Hydroarylation and Hydroalkenylation of Styrenes
Chen, Yue-Gang,Shuai, Bin,Xu, Xue-Tao,Li, Yi-Qian,Yang, Qi-Liang,Qiu, Hui,Zhang, Kun,Fang, Ping,Mei, Tian-Sheng
supporting information, p. 3395 - 3399 (2019/03/07)
We have developed a Ni-catalyzed enantioselective hydroarylation of styrenes with arylboronic acids using MeOH as the hydrogen source, providing an efficient method to access 1,1-diarylalkanes, which are essential structural units in many biologically active compounds. In addition, Ni-catalyzed enantioselective hydrovinylation of styrenes with vinylboronic acids is also realized with good yields and enantioselectivities. The synthetic utility was demonstrated by the efficient synthesis of (R)-(-)-ibuprofen.
Asymmetric synthesis via stereospecific C-N and C-O bond activation of alkyl amine and alcohol derivatives
Pound, Sarah M.,Watson, Mary P.
, p. 12286 - 12301 (2018/11/20)
This perspective showcases our development of benzylic and allylic amine and alcohol derivatives as electrophiles for stereospecific, nickel-catalyzed cross-coupling reactions, as well as the prior art that inspired our efforts. The success of our effort
