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。
Transformations of Aryl Ketones via Ligand‐Promoted C−C Bond Activation
作者:Hanyuan Li、Biao Ma、Qi‐Sheng Liu、Mei‐Ling Wang、Zhen‐Yu Wang、Hui Xu、Ling‐Jun Li、Xing Wang、Hui‐Xiong Dai
DOI:10.1002/anie.202006740
日期:2020.8.17
The coupling of aromatic electrophiles (aryl halides, aryl ethers, aryl acids, aryl nitriles etc.) with nucleophiles is a core methodology for the synthesis of aryl compounds. Transformations of arylketones in an analogous manner via carbon–carbon bond activation could greatly expand the toolbox for the synthesis of aryl compounds due to the abundance of arylketones. An exploratory study of this
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
A practical variety of o-2,3,5,6-tetrafluorobenzonitrile substituted oximes ethers bearing broad functional groups were synthesized in moderate to good yields. The key highlight of this disclosure involving a one-pot two-step tandem procedure in aqueous media: the in situ formation of aryl aldehydes or ketones oximes followed by the SNAr reaction with pentafluorobenzonitrile via the high selective
An Electrochemical Beckmann Rearrangement: Traditional Reaction via Modern Radical Mechanism
作者:Li Tang、Zhi‐Lv Wang、Yan‐Hong He、Zhi Guan
DOI:10.1002/cssc.202001553
日期:2020.9.18
electrochemical Beckmannrearrangement, i. e. the direct electrolysis of ketoximes to amides, is presented for the first time. Using a constant current as the driving force, the reaction can be easily carried out under neutral conditions at room temperature. Based on a series of mechanistic studies, a novel radical Beckmannrearrangementmechanism is proposed. This electrochemical Beckmannrearrangement does
An Easy Access to Oxime Ethers by
<scp>Pd‐Catalyzed</scp>
C—O
<scp>Cross‐Coupling</scp>
of Activated Aryl Bromides with Ketoximes and Chalcone Oximes
作者:Reeta、T. M. Rangarajan、Raj Pal Singh、R. P. Singh、Manjula Singh
DOI:10.1002/cjoc.201900540
日期:2020.8
An efficient Pd‐catalyzed method for C—O cross‐coupling of ketoximes and chalcone oximes with activated arylbromides and bromo‐chalcones has been developed. All oxime ethers were obtained in good to excellent yields by [(π‐allyl)PdCl]2/t BuXPhos (L7 ) catalyst system. TrixiePhos (L11 ) was also found to be effective for the oxime coupling. This method offers an easy and smooth coupling of chalcone
已经开发了一种有效的钯催化的方法,用于酮肟和查尔酮肟与活化的芳基溴化物和溴代查耳酮的C-O交叉偶联。通过[(π-烯丙基)PdCl] 2 / t BuXPhos(L7)催化剂体系可以很好地获得所有肟醚。还发现TrixiePhos(L11)对于肟耦合有效。该方法提供了查耳酮肟与活化的芳基溴化物和溴查耳酮的轻松,平滑的偶联,这是以前没有探索过的。