Palladium(0)-Catalyzed Cross-Coupling of 1,1-Diboronates with Vinyl Bromides and 1,1-Dibromoalkenes
作者:Huan Li、Zhikun Zhang、Xianghang Shangguan、Shan Huang、Jun Chen、Yan Zhang、Jianbo Wang
DOI:10.1002/anie.201407000
日期:2014.10.27
Palladium‐catalyzed cross‐coupling reactions of 1,1‐diboronates with vinylbromides and dibromoalkenes were found to afford 1,4‐dienes and allenes, respectively. These reactions utilize the high reactivities of both 1,1‐diboronates and allylboron intermediates generated in the initial coupling.
Synthesis of α,ω‐Bis‐Enones by the Double Addition of Alkenyl Grignard Reagents to Diacid Weinreb Amides
作者:Stefan Wiesler、Michael A. Bau、Thomas Niepel、Sara L. Younas、Hieu‐Trinh Luu、Jan Streuff
DOI:10.1002/ejoc.201901043
日期:2019.9.30
The synthesis of bis‐enones from alkenyl bromides and α,ω‐bis‐Weinreb amides via a double Grignard reaction is reported. The work contains reliable protocols for the double addition and the efficient generation of the required substituted alkenyl Grignard reagents from alkenyl bromide precursors.
Preparation of α-amino acids <i>via</i> Ni-catalyzed reductive vinylation and arylation of α-pivaloyloxy glycine
作者:Xianghua Tao、Yanchi Chen、Jiandong Guo、Xiaotai Wang、Hegui Gong
DOI:10.1039/d0sc05452f
日期:——
This work emphasizes easy access to α-vinyl and aryl amino acids via Ni-catalyzed cross-electrophile coupling of bench-stable N-carbonyl-protected α-pivaloyloxy glycine with vinyl/aryl halides and triflates. The protocol permits the synthesis of α-amino acids bearing hindered branched vinyl groups, which remains a challenge using the current methods. On the basis of experimental and DFT studies, simultaneous
这项工作强调通过Ni 催化的工作台稳定的N-羰基保护的 α-新戊酰氧基甘氨酸与乙烯基/芳基卤化物和三氟甲磺酸酯的交叉亲电偶联,轻松获得 α-乙烯基和芳基氨基酸。该协议允许合成带有受阻支链乙烯基的 α-氨基酸,这仍然是使用当前方法的挑战。在实验和 DFT 研究的基础上,可能会同时向 Ni(0) 和 Ar-Ni( II )添加甘氨酸 α-碳 (Gly) 自由基,前者在氧化添加 C(sp 2 ) 时更受青睐) 生成的 Gly-Ni( I ) 中间体的亲电体得到关键的 Gly-Ni( III )-Ar 中间体。辅助螯合Ni 中心的N-羰基氧似乎对稳定 Gly-Ni( I ) 中间体至关重要。
Nickel(II)-Magnesium-Catalyzed Cross-Coupling of 1,1-Dibromo-1-alkenes with Diphenylphosphine Oxide: One-Pot Synthesis of (<i>E</i>)-1-Alkenylphosphine Oxides or Bisphosphine Oxides
A novel nickel(II)‐magnesium‐mediated cross‐coupling of diphenylphosphine oxide with a variety of 1,1‐dibromo‐1‐alkenes has been developed, which provides a powerful and general methodology for the stereoselectivesynthesis of various (E)‐1‐alkenylphosphine oxides or bisphosphine oxides, with operational simplicity of the procedure, good to high yields and broad substrate applicability. Mechanistic
Stereodivergent Synthesis of Both <i>Z</i>- and <i>E</i>-Alkenes by Photoinduced, Ni-Catalyzed Enantioselective C(sp<sup>3</sup>)–H Alkenylation
作者:Jitao Xu、Zhilong Li、Yumin Xu、Xiaomin Shu、Haohua Huo
DOI:10.1021/acscatal.1c04314
日期:2021.11.5
The enantio- and stereoselective synthesis of stereodefined alkenes, especially the functionalized Z-isomer with an allylic stereogenic center, remains a great challenge. We herein report an enantioselective benzylic C(sp3)–H alkenylation of simple alkylarenes with vinyl bromides via photoinduced nickel catalysis, which allows for the stereodivergent synthesis of both enantioenriched Z- and E-alkenes