Palladium-Catalyzed C−H Functionalization of Pyridine <i>N</i>-Oxides: Highly Selective Alkenylation and Direct Arylation with Unactivated Arenes
作者:Seung Hwan Cho、Seung Jun Hwang、Sukbok Chang
DOI:10.1021/ja8026295
日期:2008.7.1
Two catalytic protocols of the oxidative C-C bond formation have been developed on the basis of the C-H bond activation of pyridine N-oxides. Pd-catalyzed alkenylation of the N-oxides proceeds with excellent regio-, stereo-, and chemoselectivity, and the corresponding ortho-alkenylated N-oxide derivatives are obtained in good to excellent yields. Direct cross-coupling reaction of pyridine N-oxides
在吡啶 N-氧化物的 CH 键活化的基础上开发了两种氧化 CC 键形成的催化方案。Pd 催化的 N-氧化物的烯基化以优异的区域选择性、立体选择性和化学选择性进行,并且相应的邻位烯基化 N-氧化物衍生物以良好到优异的产率获得。在 Pd 催化剂和 Ag 氧化剂的存在下,还开发了吡啶 N-氧化物与未活化芳烃的直接交叉偶联反应,这提供了具有高位点选择性的邻芳基化吡啶 N-氧化物产物。
Reaction of pyrylium salts with nucleophiles. Part 25. Formation of pyridine-1-oxides, 2-isoxazolines and 1-pyrazoline-1-oxides
作者:Cornelia Uncuta、Miron Teodor Cǎproiu、Valentin Câmpeanu、Aurica Petride、Mariana G Dǎnilǎ、Marieta Plǎveti、Alexandru T Balaban
DOI:10.1016/s0040-4020(98)00530-4
日期:1998.8
The reaction of tri- and tetrasubstituted pyryliumsalts with hydroxylamine affords acyclic keto-ketoximes (to be described in a separate paper) which cyclize yielding pyridine-1-oxides and/or 2-isoxazolines. Both these classes of compounds, with many possible applications, can thus be obtained simply and in good yield. The regioselectivity of 2-isoxazoline formation from unsymetrically substituted
Beckmann and cyclization reactions of δ-oxo-α,β-unsaturated ketoximes obtained from pyrylium salts and hydroxylamine. formation of 2-aryl(or alkyl)amino-4,6-disubstituted pyrylium salts
The reaction of 2,4,6-trisubstituted pyryliumsalts 1 with hydroxylamine gave regio- and stereo-selectively 1,3,5-trisubstituted 2-cis-pentene-1,5-dione 1-oximes 4. On cyclization, 3,5,5-trisubstituted 2-isoxazolines 6 and 2,4,6-trisubstituted pyridine 1-oxides 5 were obtained, originating in the antilsyn stereoisomers of oxime 4, respectively. Beckmann reaction of keto-ketoximes 4 with thionyl chloride
Strong N−X⋅⋅⋅O−N Halogen Bonds: A Comprehensive Study on N‐Halosaccharin Pyridine
<i>N</i>
‐Oxide Complexes
作者:Rakesh Puttreddy、J. Mikko Rautiainen、Toni Mäkelä、Kari Rissanen
DOI:10.1002/anie.201909759
日期:2019.12.16
A study of the strong N-X⋅⋅⋅- O-N+ (X=I, Br) halogen bonding interactions reports 2×27 donor×acceptor complexes of N-halosaccharins and pyridine N-oxides (PyNO). DFTcalculations were used to investigate the X⋅⋅⋅O halogen bond (XB) interaction energies in 54 complexes. A simplified computationally fast electrostatic model was developed for predicting the X⋅⋅⋅O XBs. The XB interaction energies vary
N−X⋅⋅⋅O−N Halogen Bonds in Complexes of <i>N</i>‐Haloimides and Pyridine‐<i>N</i>‐oxides: A Large Data Set Study
作者:Rakesh Puttreddy、J. Mikko Rautiainen、Shilin Yu、Kari Rissanen
DOI:10.1002/anie.202307372
日期:2023.8.21
large data set of X⋅⋅⋅O halogen bonds in N-haloimide-pyridine-N-oxide complexes has been compiled from 132 DFT-optimized structures, 75 crystal structures, and 168 1H NMR titrations. This approach has led to unprecedented correlations being found between the DFT halogen bond interaction energies (E) derived from only three key parameters: the sigma-hole of the XB donor halogen, the atomic charge, and
N-卤代酰亚胺-吡啶-N-氧化物配合物中的 X⋅⋅⋅O 卤素键的大型数据集已由 132 个 DFT 优化结构、75 个晶体结构和 168 个1 H NMR 滴定汇编而成。这种方法导致在仅源自三个关键参数的DFT 卤键相互作用能 ( E ) 之间发现了前所未有的相关性:XB 供体卤素的西格玛空穴、原子电荷和氧原子的局部电离能。