Efficient synthesis of 1,2,4-oxadiazine-5-ones via [3+3] cycloaddition of in situ generated aza-oxyallylic cations with nitrile oxides

Recent Advances in Silver‐Mediated Radical Difunctionalization of Alkenes

“…in 2018, in which 10 mol % of AgNO 3 were employed as catalyst (Scheme 48). [58] Other transition‐metals such as FeCl 2 , FeCl 3 , CuCl 2 and CoCl 2 were effective in this 1,2‐difunctionalization reaction, but gave lower yield of product. A variety of styrene derivatives were well tolerated in the reaction progress and gave the β ‐sulfonyl peroxides in 44–96 % yields, which could be further converted into various sulfone derivatives.…”

[3+3] Cycloaddition Reactions of Aza-oxyallyl Cations with Oximes: Synthesis of 2-N-Unsubstituted 1,2,4-Oxadiazinan-5-ones

“…m.p. 156～158 ℃; 1 H NMR (400 MHz, CDCl 3 ) δ: 7.49～7.42 (m, 5H), 7.36～7.25 (m, 3H), 7.16～7.04 (m, 2H), 4.98 (d,J＝10.1 Hz,1H),4.87 (s,1H),4.85 (s,1H),4.47 (d,J＝10.2 Hz,1H),1.35 (s,3H), 1.27 (s, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ: 170.0, 135. 1, 134.4, 129.9, 129.8, 129.3, 129.1, 128.5, 128.5, 80.7, 78.1, 64.4, 23.2, 16 4-(苄氧基)-6,6-二甲基-3-(4-甲苯基)-1,2,4-噁二嗪-5-酮(3b): 白色固体, 产率 98%.…”

“…162～164 ℃; 1 H NMR (400 MHz, CDCl 3 ) δ: 7.33～7.25 (m, 5H), 7.22 (d, J＝7.9 Hz, 2H), 7.12 (d, J＝7.9 Hz, 2H), 4.98 (s, 1H), 4.95 (d,J＝10.3 Hz,1H),4.78 (s,1H),4.47 (d,J＝10.3 Hz,1H), 2.40 (s, 3H), 1.29 (s, 3H), 1.22 (s, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ: 170.0, 139. 9, 134.5, 132.0, 129.8, 129.2, 129.0, 128.4, 80.5, 77.95, 64.3, 23.2, 21.4, 16 8, 134.5, 130.54, 129.8, 129.1, 128.4, 126.9, 113.9, 80.2, 64.3, 55.4, 23.3, 16 (d,J＝10.4 Hz,1H),4.89 (s,1H),4.78 (s,1H),4.49 (d,J＝10.4 Hz,1H), 1.34 (s, 3H), 1.25 (s, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ: 170. 1, 164.9, 162.4, 134.4, 131.1, 131.0, 130.9, 130.8, 129.8, 129.2, 128.5, 115.6, 115.4, 80.0, 64.4, 23.3, 16 4-(苄氧基)-3-(4-溴苯基)-6,6-二甲基-1,2,4-噁二嗪-5-酮(3e): 白色固体, 产率 89%.…”

“…值得一 提的是, 该类 1,3-偶极体通过与不同的硝酮类化合物发 [8] , Zhao [9] 和 Wang [10] 课题组分别将其 与不同类型的硝酮反应, 以良好的收率得到对应的 1,2,4-噁二嗪-5-酮衍生物. Chen 研究组 [11] 将其与靛红硝 酮反应得到相应的螺 [1,2,4- 肟通常作为腈的氮氧化物前体, 转化成腈的氮氧化 物后才能作为 1,3-偶极体发生环加成反应 [12] , 有关这方 面的研究有很多报道; 最近, 腈的氮氧化物与氮氧烯丙 基正离子的[3＋3]环加成反应也有报道 [13] . 然而, 由于 肟的活性低, 作为 1,3-偶极体直接发生环加成反应的研 究却非常少.…”

Synthesis of spiro(indoline‐3,1′‐pyrazolo[1,2‐a]pyrazoles) by 1,3‐dipolar cycloadditions of isatin N,N′‐cyclic azomethine imines with alkynes

“…Our research team has been interested in the development of novel dipolar cycloaddition reactions for the synthesis of biologically active heterocycles . Recently, a new type of azomethine imine dipolar, isatin N,N′ ‐cyclic azomethine imine, has caught our attention due to its unique structure.…”