Asymmetric Synthesis of Nonracemic Primary Amines via Spiroborate-Catalyzed Reduction of Pure (<i>E</i>)- and (<i>Z</i>)-<i>O</i>-Benzyloximes: Applications toward the Synthesis of Calcimimetic Agents
作者:Wenhua Ou、Sandraliz Espinosa、Héctor J. Meléndez、Silvia M. Farré、Jaime L. Alvarez、Valerie Torres、Ileanne Martínez、Kiara M. Santiago、Margarita Ortiz-Marciales
DOI:10.1021/jo400371x
日期:2013.6.7
Highly enantiopure (1-aryl)- and (1-naphthyl)-1-ethylamines were synthesized by the borane-mediated reduction of single-isomeric (E)- and (Z)-O-benzyloxime ethers using the stable spiroborate ester derived from (S)-diphenyl valinol and ethylene glycol as the chiral catalyst. Primary (R)-arylethylamines were prepared by the reduction of pure (Z)-ethanone oxime ethers in up to 99% ee using 15% of catalyst
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。
Cyanuric Chloride as a Mild and Active Beckmann Rearrangement Catalyst
organocatalytic Beckmannrearrangement of ketoximes into amides has been realized by the catalytic use of cyanuric chloride. Furthermore, acids such as HCl and ZnCl2 are effective as cocatalysts with cyanuric chloride. For example, azacyclotridecan-2-one, which is synthetically useful as a starting material for nylon-12, was prepared in quantitative yield by the Beckmannrearrangement of cyclododecanone
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。
Enantioselective Hydrogenation of Activated Aryl Imines Catalyzed by an Iron(II) P-NH-P′ Complex
作者:Chris S. G. Seo、Thibault Tannoux、Samantha A. M. Smith、Alan J. Lough、Robert H. Morris
DOI:10.1021/acs.joc.9b01964
日期:2019.9.20
industries. Asymmetric imine hydrogenation, particularly with iridium catalysts, is well developed. However, imine reduction still remains challenging in the context of replacing such a precious metal with a cheap, nontoxic, and environmentally friendly substitute such as iron. Here, we report that an unsymmetrical iron P-NH-P′ catalyst that was previously shown to be effective for the asymmetric hydrogenation
手性胺是合成化学的关键组成部分,在农业和制药工业中有许多应用。不对称的亚胺氢化,特别是使用铱催化剂的氢化,已经得到了很好的发展。但是,在用廉价,无毒且环保的替代品(例如铁)替代这种贵金属的背景下,还原亚胺仍然具有挑战性。在这里,我们报道先前被证明对芳基酮的不对称氢化有效的不对称铁P-NH-P'催化剂,对于被N-二苯基膦酰基或N活化的前手性芳基亚胺的不对称氢化也是非常有效的催化剂。-甲苯磺酰基。P-NH-P'的缩写表示(S,S)-PPh 2CHPhCHPhNHCH 2 CH 2 P i Pr 2。密度泛函理论结果表明,出人意料的是,与亚胺氮本身相反,催化剂上的NH基团通过与亚胺氮上的PO或SO基的氢键键合而使亚胺受氢化物的攻击而活化。这可以解释为什么N -Ph和N- Bu亚胺不被氢化。
An Efficient and Versatile One-Pot Beckmann Rearrangement of Ketoximes Using Mesitylenesulfonyl Chloride
作者:Yong-Tae Park、Chennan Ramalingan
DOI:10.1055/s-2008-1042948
日期:2008.5
acyclic ketoximes in the presence of lithium hydroxide in tetrahydrofuran, efficiently rearrange into their corresponding lactams and amides. The stereo-chemistry of diazepan-5-one lactams resulting from the rearrangement of heterocyclic ketoximes (piperidin-4-one oximes), has been deduced based on one- and two-dimensional NMR analyses. The seven-membered heterocyclic ring of the product lactams adopts chair