使用衍生自稳定的螺硼酸酯,通过硼烷介导的单一异构体 ( E )- 和 ( Z ) -O-苄基肟醚的还原,合成了高对映体纯的 (1-芳基)-和 (1-萘基)-1-乙胺( S )-二苯基缬氨醇和乙二醇作为手性催化剂。伯 ( R )-芳基乙胺是通过使用 15% 的催化剂将纯 ( Z )-乙酮肟醚还原至 99% ee来制备的。描述了使用对映纯(1-萘-1-基)乙胺作为手性前体合成新的和已知的拟钙剂类似物的两种方便且容易的方法。
A mild and efficient protocol for the synthesis of 2,2′-difunctional biaryls from readily available benzamides and oximes by Co(OAc)2·4H2O catalysis has been developed. The catalytic cycle that includes aerobic oxidation of Co(I) to Co(III) is successfully achieved for the first time through dual-chelation-assisted C–H/C–H coupling with the assistance of catalytic Mn(acac)3. The catalytic system exhibits
Cp*-Free Cobalt-Catalyzed C–H Activation/Annulations by Traceless <i>N</i>,<i>O</i>-Bidentate Directing Group: Access to Isoquinolines
作者:Xiao-Cai Li、Cong Du、He Zhang、Jun-Long Niu、Mao-Ping Song
DOI:10.1021/acs.orglett.9b00866
日期:2019.4.19
N,O-Bidentate directing-enabled, traceless heterocycle synthesis is described via Cp*-free cobalt-catalyzedC–Hactivation/annulation. The weakly coordinating nature of the carboxylic acid was employed for the preparation of isoquinolines. Meanwhile, the N–Obond of the α-imino-oxy acid can serve as an internaloxidant. Terminal as well as internalalkynes can be efficiently applied to the catalytic
One-pot synthesis of 2-amino-3,4-dicyanopyridines from ketoximes and tetracyanoethylene via Cu(I)-catalyzed cyclization
作者:Ziwei Han、Jianguang Lv、Jianmin Zhang
DOI:10.1016/j.tet.2019.02.032
日期:2019.4
A novel approach to 2-amino-3,4-dicyanopyridines has been discovered fromCu(I)-catalyzed cyclizations of simple and easily available ketoximes and tetracyanoethylene (TCNE). The complexed radical mechanism involves cleavage of several OH/NO/CH bonds, and new CC/CN bonds formation. A wide variety of substrates with different functional groups could be smoothly converted into the corresponding products
从Cu(I)催化的简单易得的酮肟和四氰基乙烯(TCNE)的环化反应中发现了一种2-氨基-3,4-二氰基吡啶的新颖方法。复杂的自由基机制涉及几个O H / N O / C H键的断裂,以及新的C C / C N键的形成。可以将具有不同官能团的多种底物以中等收率平稳地转化为相应的产品。
Copper-catalyzed synthesis of oxime ethers from iminoxy radical (C N–O ) and maleimides via radical addition
identified copper catalyst enables the formation of oxime radicals (N–O) by cleaving the O–H bond in ketoximes, followed by the radical addition to N-substituted maleimides. The oxime radicals (N–O) were detected and confirmed by EPR spectroscopy and variable-temperature 1H NMR. The simple one-pot reaction realizes the facile preparation of a variety of oximeether adduct products in moderate to good yields
已经实现了高效的Cu(II)催化的马来酰亚胺自由基加成。鉴定出的铜催化剂可通过裂解酮肟中的O-H键,然后将自由基添加到N-取代的马来酰亚胺中,从而形成肟自由基(N-O )。通过EPR光谱和可变温度1 H NMR检测并确认了肟自由基(NO )。简单的一锅反应可轻松制备中度到良好收率的各种肟醚加合物产物。