KI/TBHP-mediated oxidative cross coupling of enamines with carboxylic acids has been realized for the synthesis of functionalized 2H-azirines through the azirination of enamine intermediates. The metal-free strategy has several notable features, including the formation of C–O and C–N bonds in a one-pot procedure, broad functional group tolerance, good reaction yields, short reaction time, and high
KI / TBHP介导的烯胺与羧酸的氧化交叉偶联已通过烯胺中间体的叠氮化反应用于官能化2 H-叠氮基的合成。不含金属的策略具有几个显着特征,包括在一锅法中形成C-O和C-N键,官能团耐受性广,反应产率高,反应时间短和原子经济性高。这是通过KI / TBHP介导的烯胺和羧酸的分子间交叉偶联直接形成官能化的2 H-叠氮基的第一个例子。
Photocycloaddition of aromatic and aliphatic aldehydes to isoxazoles: Cycloaddition reactivity and stability studies
作者:Axel G Griesbeck、Marco Franke、Jörg Neudörfl、Hidehiro Kotaka
DOI:10.3762/bjoc.7.18
日期:——
The first photocycloadditions of aromatic and aliphatic aldehydes to methylated isoxazoles are reported. The reactions lead solely to the exo-adducts with high regio- and diastereoselectivities. Ring methylation of the isoxazole substrates is crucial for high conversions and product stability. The 6-arylated bicyclic oxetanes 9a-9c were characterized by X-ray structure analyses and showed the highest
报道了芳香族和脂肪族醛对甲基化异恶唑的首次光环加成反应。该反应仅导致具有高区域选择性和非对映选择性的外加合物。异恶唑底物的环甲基化对于高转化率和产品稳定性至关重要。6-芳基化双环氧杂环丁烷 9a-9c 通过 X 射线结构分析表征并显示出最高的热稳定性。由异恶唑形成的所有氧杂环丁烷都对酸高度敏感且热不稳定。对原始底物的裂解占主导地位,异恶唑衍生的氧杂环丁烷显示 T 型光致变色。
Vinylnitrene Formation from 3,5-Diphenyl-isoxazole and 3-Benzoyl-2-phenylazirine
作者:Disnani W. Gamage、Qian Li、R. A. A. Upul Ranaweera、Sujan K. Sarkar、Geethika K. Weragoda、Patrick L. Carr、Anna D. Gudmundsdottir
DOI:10.1021/jo401819g
日期:2013.11.15
forming 4 in argon-saturated acetonitrile is 1.6 × 107 s–1. In oxygen-saturated acetonitrile, vinylnitrene 4 reacts to form the peroxide radical 6 (λmax 360 nm, ∼0.7 μs, acetonitrile) at a rate of 2 × 109 M–1 s–1. Density functional theory calculations were performed to aid in the characterization of vinylnitrene 4 and peroxide 6 and to support the proposed mechanism for the formation of these intermediates
在氩气饱和的乙腈中进行1的光解,得到2,而在氧饱和的乙腈中,除2之外还形成少量的苯甲酸和苯甲酰胺。类似地,在氩气饱和的乙腈中光解2的结果为1,痕量为3,而在氧饱和的乙腈中,除了少量的苯甲酸和苯甲酰胺的形成,主要产物为1。激光闪光光解为1时,由于三重态亚硝酸乙烯酯4导致吸收(宽吸收,λmax在360 nm处,τ= 1.8μs,乙腈)以1.2×10 7 s –1的速率常数形成,并以5.6×10 5 s –1的速率常数衰减。氩气饱和乙腈中2的激光闪光光解同样会导致形成三重态乙烯-亚硝酸丁烯4以及叶立德5(在440 nm处的λmax,τ= 13μs )。在氩气饱和的乙腈中形成4的速率常数为1.6×10 7 s –1。在氧饱和的乙腈中,亚乙烯基四烯4反应形成过氧化物自由基6(λmax360 nm,〜0.7μs,乙腈),速率为2×10 9 M –1 s –1。进行了密度泛函理论计算,以帮助表征乙烯基
A Copper‐Catalyzed Synthesis of Pyrroles through Photochemically Generated Acylazirines
作者:Jan Paternoga、Till Opatz
DOI:10.1002/ejoc.201901176
日期:2019.11.14
A protocol for the synthesis of highly substituted 2,4‐diacypryrroles via a copper‐catalyzed ring strain releasing dimerization reaction was developed. The pyrroles are synthesized combining UV–photochemistry and metal‐catalyzed follow up reaction in an one‐pot system. To match the rates of the thermal and the photoinduced step, an internal temperature control was established.
SYNTHESIS OF TRISUBSTITUTED 4<i>H</i>-1,2,4-OXADIAZINES
作者:Shonosuke Zen、Kazuho Harada
DOI:10.1246/cl.1982.1711
日期:1982.11.5
The derivatives of 4H-1,2,4-oxadiazine, a new class of six-membered heterocycles, were synthesized through the reactions of β-diketones with aliphatic nitro compounds and acetyl chloride, and also of azirines with nitrile oxides. A reaction mechanism is proposed.