Aza-heterocycles via copper-catalyzed, remote C–H desaturation of amines
作者:Leah M. Stateman、Ross M. Dare、Alyson N. Paneque、David A. Nagib
DOI:10.1016/j.chempr.2021.10.022
日期:2022.1
desaturation of amines. Inspired by the Hofmann-Löffler-Freytag (HLF) synthesis of five-membered pyrrolidines, we tackled the century-old challenge of synthesizing six-membered piperidines by H-atom transfer. Herein, we present a double, vicinal C–H oxidation by dual catalysis, entailing Ir photocatalytic initiation of 1,5-HAT by an N-centered radical and Cu-catalyzed interception of the C-centered radical
大多数药物在五元或六元环中含有一个氮原子。为了快速获得这两种氮杂杂环化合物,我们试图开发一种远程 C-H 胺去饱和方法。受五元吡咯烷的 Hofmann-Löffler-Freytag (HLF) 合成的启发,我们解决了通过氢原子转移合成六元哌啶的百年挑战。在这里,我们提出了一个 双,通过双催化进行邻位 C-H 氧化,需要 Ir 光催化引发 1,5-HAT 由 N 中心自由基和 Cu 催化拦截 C 中心自由基以促进去饱和。通过这种机制,两个 C-H 键(δ 和 ε 到 N)被区域选择性地从烷基链的无偏、远程位置移除。超过 50 个实例说明了合成内部和末端 δ 乙烯基胺和氮杂杂环的效率、选择性、官能团耐受性和药用价值。机理实验探索了烷基铜中间体,以及 HAT 和消除步骤的动力学和区域选择性。
Palladium-Catalyzed Intramolecular Aminoacetoxylation of Unactivated Alkenes with Hydrogen Peroxide as Oxidant
作者:Haitao Zhu、Pinhong Chen、Guosheng Liu
DOI:10.1021/acs.orglett.5b00373
日期:2015.3.20
A palladium-catalyzed intramolecular aminoacetoxylation of unactivated alkenes was developed in which H2O2 was used as the sole oxidant. A variety of 3-acetoxylated piperidines were obtained in good yields with good to excellent regio- and diastereoselectivities. Mechanistic study revealed that the addition of di(2-pyridyl) ketone (dpk) ligand was crucial to promote the oxidative cleavage of the C–Pd(II)
开发了钯催化的未活化烯烃的分子内氨基乙酰氧基化反应,其中H 2 O 2被用作唯一的氧化剂。以良好的产率获得了各种3-乙酰氧基化的哌啶,具有良好或优异的区域和非对映选择性。机理研究表明,添加二(2-吡啶基)酮(dpk)配体对于促进H 2 O 2氧化C-Pd(II)键产生C-OAc键至关重要。
Preparation of selenofunctionalized heterocycles via iodosobenzene-mediated intramolecular selenocyclizations of olefins with diselenides
An intramolecular selenocyclizations of olefins mediated by a commercially available hypervalent iodine(III) reagent, PhIO, was developed. This method provided access to a wide range of selenenylated heterocycles under ambient conditions. The striking advantages of this protocol over all previous methods include mild reaction conditions, easy operation, good yields, high levels of functional group
Palladium-Catalyzed Alkene Carboamination Reactions of Electron-Poor Nitrogen Nucleophiles
作者:Luke J. Peterson、John P. Wolfe
DOI:10.1002/adsc.201500334
日期:2015.7.6
Modified reaction conditions that facilitate Pd‐catalyzed alkene carboamination reactions of electron‐deficient nitrogennucleophiles are reported. Pent‐4‐enylamine derivatives bearing N‐tosyl or N‐trifluoroacetyl groups are coupled with aryl triflates to afford substituted pyrrolidines in good yield. These reactions proceed via a mechanism involving anti‐aminopalladation of the alkene, which differs
1 bearing an amino group protected by an electron-withdrawing group were smoothly cyclized to 2-(silylmethyl)pyrrolidines 2. This cyclization was utilized for the stereoselectivesynthesis of 2,n-disubstituted pyrrolidines (n = 3-5). The cyclized products could be converted to the corresponding alcohols by oxidative cleavage of the carbon-silicon bond with TBAF and H2O2.
[反应:见正文]在酸催化剂的存在下,将带有被吸电子基团保护的氨基的乙烯基硅烷1平滑环化为2-(甲硅烷基甲基)吡咯烷2。该环化反应用于2的立体选择性合成正二取代的吡咯烷(n = 3-5)。通过用TBAF和H 2 O 2氧化碳-硅键,可以将环化产物转化为相应的醇。