我们开发了一种通过对映体富集的苄基三环己基锡亲核试剂的立体特异性钯催化交叉偶联反应形成对映体富集的苄基立构中心的通用方法。该过程对非常广泛的亲电偶联配偶体具有优异的立体特异性,包括芳基和杂芳基卤化物和三氟甲磺酸酯、酰基氯、硫酯、氯甲酸酯和氨基甲酰氯。因此,使用这种方法可以很容易地获得对映体富集的 1,1-二芳基烷烃以及不对称烯醇化芳基化的正式产物。我们还首次演示了使用邻位烷基硼基锡烷亲核试剂进行 Sn 选择性交叉偶联反应。在这些反应中,锡上环己基旁观配体的存在对于确保仲苄基单元从锡选择性转移至钯至关重要。
Cobalt co-catalysis for cross-electrophile coupling: diarylmethanes from benzyl mesylates and aryl halides
作者:Laura K. G. Ackerman、Lukiana L. Anka-Lufford、Marina Naodovic、Daniel J. Weix
DOI:10.1039/c4sc03106g
日期:——
of aryl halides with alkyl radicals derived fromalkyl halides has recently been extended to couplings with carbon radicals generated by a co-catalyst. In this study, a new co-catalyst, cobalt phthalocyanine (Co(Pc)), is introduced and demonstrated to be effective for coupling substrates not prone to homolysis. This is because Co(Pc) reacts with electrophiles by an SN2 mechanism instead of by the electron-transfer
镍催化的芳基卤化物与衍生自烷基卤化物的烷基的交叉偶联最近已扩展到与助催化剂产生的碳自由基的偶联。在这项研究中,引入了一种新的助催化剂——酞菁钴(Co(Pc)),并被证明对偶联不易均裂的底物有效。这是因为 Co(Pc) 通过 S N 2 机制而不是之前探索的电子转移或卤素抽象机制与亲电子试剂发生反应。研究证明了 (bpy)Ni 和 Co(Pc) 的正交反应性,将这种选择性应用于甲磺酸苄酯与芳基卤的偶联,以及将这些条件适应于反应性较低的磷酸苄酯和对映体收敛反应。
Nickel-Catalyzed Asymmetric Hydroarylation of Vinylarenes: Direct Enantioselective Synthesis of Chiral 1,1-Diarylethanes
作者:Hai N. Tran、Russell W. Burgett、Levi M. Stanley
DOI:10.1021/acs.joc.0c02556
日期:2021.3.5
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
Suzuki–Miyaura cross-couplings of secondary allylic boronic esters
作者:Ben W. Glasspoole、Kazem Ghozati、Jonathon W. Moir、Cathleen M. Crudden
DOI:10.1039/c2cc16076e
日期:——
Palladium-catalyzed cross-coupling reactions of secondary allylic boronic esters with iodoarenes were demonstrated under the conditions previously described for the coupling of benzylic substrates. The regioselectivity of the process was largely dictated by the pattern of olefin substitution.
Enantioselective Reductive
<scp>Cross‐Coupling</scp>
of Aryl/Alkenyl Bromides with Benzylic Chlorides
<i>via</i>
Photoredox/Biimidazoline Nickel Dual Catalysis
作者:Tongtong Li、Xiaokai Cheng、Jiamin Lu、Huifeng Wang、Qun Fang、Zhan Lu
DOI:10.1002/cjoc.202100819
日期:2022.5
The asymmetric reductive arylation and alkenylation of benzylic chloride under photoredox/nickel dual catalysis using chiral biimidazoline (BiIm) ligand is reported to access 1,1-diaryl alkanes and aryl allylic compounds with good yield as well as stereo- and enantioselectivities. This protocol uses more commercially available and less expensive C(sp2)-Br as the electrophile coupling partner. A primary
Nickel-Catalyzed Regiodivergent Reductive Hydroarylation of Styrenes
作者:Yuli He、Shaolin Zhu、Yuhang Xue、Jian Chen、Peihong Song
DOI:10.1055/a-1523-3228
日期:2021.10
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