Single‐Step Modular Synthesis of Unsaturated Morpholine
<i>N</i>
‐Oxides and Their Cycloaddition Reactions
作者:Jongwoo Son、Ki Hwan Kim、Dong‐Liang Mo、Donald J. Wink、Laura L. Anderson
DOI:10.1002/anie.201611791
日期:2017.3.6
A single‐flask procedure for the generation of α‐keto‐N‐alkenylnitrones through a Chan–Lam coupling and subsequent spontaneous 6π electrocyclization of these intermediates for the synthesis of 2H‐1,4‐oxazine N‐oxides has been developed for a variety of α‐ketooximes and alkenylboronic acids. This transformation provides a new approach to C‐substituted unsaturated morpholine derivatives that are poised
为的α酮的生成单烧瓶过程Ñ -alkenylnitrones通过浐榄耦合和这些中间体的后续自发6πelectrocyclization 2的合成ħ -1,4-恶嗪Ñ -oxides已为开发各种α-酮肟酸和烯基硼酸。这种转变为C取代的不饱和吗啉衍生物提供了一种新方法,该衍生物准备进行进一步的功能化,以制备各种新颖的杂环结构。除了描述这些新杂环中间体的环加成反应性的初步研究之外,还讨论了合成2 H -1,4-恶嗪N-氧化物的新方法的范围。
Asymmetric Reduction of α-Keto Aldoxime O-Ethers
作者:Mariusz Bosiak、Marcin Pakulski
DOI:10.1055/s-0030-1258355
日期:2011.1
The catalytic asymmetric reduction of α-keto aldoxime O-methyl, O-benzyl, and O-trityl ethers, derived from substituted acetophenones, with borane/oxazaborolidines, by transfer hydrogenation, and with yeast, was studied. The reduction with borane/oxazaborolidines produced the corresponding α-hydroxy oxime ethers, α-hydroxy hydroxylamine ethers, and β-amino alcohols in 39-78% yields and up to 77% ee. The carbonyl group was selectively reduced by transfer hydrogenation with formic acid-triethylamine catalyzed by RhCl[(R,R)-TsDPEN](C5Me5), and also with yeast, producing α-hydroxy oxime ethers, up to 75% ee and 93% ee, respectively.
Water-mediated decarboxylative radical nitrosation of β-keto acids with <i>tert</i>-butyl nitrite: access to α-oximino ketones
作者:Lina Jia、Linlin Li、Fuzhong Han、Xiangping Hu
DOI:10.1039/d2nj04175h
日期:——
A practical catalyst-free decarboxylative radical nitrosation reaction of β-keto acids with tert-butyl nitrite in water was developed. The strategy involving radicals worked well under relatively mild conditions. This protocol presented an efficient route for the construction of various aromatic and aliphatic α-oximino ketones with different electronic and steric properties in good to excellent yields
An efficient route to 5-(hetero)aryl-2,4′- and 2,2′-bipyridines through readily available 3-pyridyl-1,2,4-triazines
作者:Valery N. Kozhevnikov、Dmitry N. Kozhevnikov、Olga V. Shabunina、Vladimir L. Rusinov、Oleg N. Chupakhin
DOI:10.1016/j.tetlet.2005.01.135
日期:2005.3
A new route to substituted bipyridines based on a new method for the synthesis of substituted 3-pyridyl-1,2,4-triazines and their aza-Diels-Alder reactions is shown to be an efficient strategy for the preparation of structurally diverse bipyridine ligands. (C) 2005 Elsevier Ltd. All rights reserved.