Directing Group‐Promoted Inert C−O Bond Activation Using Versatile Boronic Acid as a Coupling Agent
作者:Ram Ambre、Ting‐Hsuan Wang、Anmei Xian、Yu‐Shiuan Chen、Yu‐Fu Liang、Titel Jurca、Lili Zhao、Tiow‐Gan Ong
DOI:10.1002/chem.202004132
日期:2020.12.18
strategy facilitates the efficient catalytic cross‐coupling of methoxyarenes with a variety of organoboronreagents. Directing groups facilitate the activation of inert C−O bonds in under‐utilized aryl methyl ethers enabling their adaptation for C−C cross‐coupling reactions as less toxic surrogates to the ubiquitous haloarenes. The method reported enables C−C cross‐coupling with readily available and economical
Rad transition: The combination of transition‐metal‐catalyzed CHactivation and a NHPI‐initiated radical process is essential for the title transformation. The neutral conditions and the ideal oxidant, molecular oxygen, make this hydroxylation environmentally friendly and practical. NHPI=N‐hydroxyphthalimide.
Enantioselective Synthesis of α-(Hetero)aryl Piperidines through Asymmetric Hydrogenation of Pyridinium Salts and Its Mechanistic Insights
作者:Bo Qu、Hari P. R. Mangunuru、Sergei Tcyrulnikov、Daniel Rivalti、Olga V. Zatolochnaya、Dmitry Kurouski、Suttipol Radomkit、Soumik Biswas、Shuklendu Karyakarte、Keith R. Fandrick、Joshua D. Sieber、Sonia Rodriguez、Jean-Nicolas Desrosiers、Nizar Haddad、Keith McKellop、Scott Pennino、Heewon Lee、Nathan K. Yee、Jinhua J. Song、Marisa C. Kozlowski、Chris H. Senanayake
DOI:10.1021/acs.orglett.8b00067
日期:2018.3.2
α-heteroaryl piperidines is reported. The key step is an iridium-catalyzed asymmetric hydrogenation of substituted N-benzylpyridinium salts. High levels of enantioselectivity up to 99.3:0.7 er were obtained for a range of α-heteroaryl piperidines. DFT calculations support an outersphere dissociative mechanism for the pyridinium reduction. Notably, initial protonation of the final enamine intermediate
报道了 α-芳基和 α-杂芳基哌啶的对映选择性合成。关键步骤是取代的N-苄基吡啶鎓盐的铱催化不对称氢化。一系列 α-杂芳基哌啶获得了高达 99.3:0.7 er 的高水平对映选择性。DFT 计算支持吡啶还原的外层解离机制。值得注意的是,最终烯胺中间体的初始质子化决定了转化的立体化学结果,而不是所得亚胺中间体的氢化物还原。
[EN] AROMATIC MONOMER-AND CONJUGATED POLYMER-METAL COMPLEXES<br/>[FR] COMPLEXES METALLIQUES A BASE DE MONOMERE AROMATIQUE ET DE POLYMERE CONJUGUE
申请人:DOW GLOBAL TECHNOLOGIES INC
公开号:WO2005016945A1
公开(公告)日:2005-02-24
A halogenated aromatic monomer-metal complex useful for preparing a polymer for electronic devices such as a light-emitting diode (LED) device is described. The aromatic monomer-metal complex is designed to include a linking group that disrupts conjugation, thereby advantageously reducing or preventing electron delocalization between the aromatic monomer fragment and the metal complex fragment. Disruption of conjugation is often desirable to preserve the phosphorescent emission properties of the metal complex in a polymer formed from the aromatic monomer-metal complex. The resultant conjugated electroluminescent polymer has precisely controlled metal complexation and electronic properties that are substantially or completely independent of those of the polymer backbone.
A novel Pd-catalyzed nitrogenation of arylpyridines via C-H azidation has been developed. Direct C-N and N-N formations are achieved for this N-atom incorporation transformation using azides as the N-atom source. This method provides an alternatively concise approach for the construction of bioactively important pyrido[1,2-b]indazoles.