Selective Synthesis of Indazolo[2,3‐
<i>a</i>
]quinolines via Rh(III)‐Catalyzed Oxidant‐Free [4+2] or [5+1] Annulation of 2‐Aryl‐2
<i>H</i>
‐indazoles with
<i>α</i>
‐Diazo Carbonyl Compounds
作者:Shenghai Guo、Lincong Sun、Xuzhuo Li、Xinying Zhang、Xuesen Fan
DOI:10.1002/adsc.201901422
日期:2020.2.21
A selective synthesis of 5,6‐disubstituted and 5‐substituted indazolo[2,3‐a]quinolines through a Rh(III)‐catalyzed oxidant‐free annulation of 2‐aryl‐2H‐indazoles with α‐diazo carbonyl compounds is reported. With 2‐aryl‐2H‐indazoles as the substrates, α‐diazo carbonyl compounds could act as a C2 synthon to afford 5,6‐disubstituted indazolo[2,3‐a]quinolines via a Rh(III)‐catalyzed [4+2] annulation. On
通过Rh(III)催化的2-芳基-2 H-吲唑与α-重氮羰基化合物的无氧化剂环氧化反应选择性合成5,6-二取代和5-取代的吲唑并[2,3- a ]喹啉是报告。以2-芳基-2 H-吲唑为底物,α-重氮羰基化合物可作为C2合成子,通过Rh(III)催化[ 5,6-二取代的吲唑并[2,3- a ]喹啉] [4 +2]。另一方面,当使用2-芳基-3-甲酰基-2 H-吲唑类作为底物时,α-重氮羰基化合物转变为C1合成子,需要经历更复杂的[5 + 1]环化工艺来提供5位取代的吲哚并[2,3- a ]喹啉。
Reduction of nitro- and nitroso-compounds by tervalent phosphorus reagents. Part XI. A kinetic study of the effects of varying the reagent and the nitro-compound in the conversion of o-nitrobenzylideneamines to 2-substituted indazoles
作者:Margaret-Ann Armour、J. I. G. Cadogan、David S. B. Grace
DOI:10.1039/p29750001185
日期:——
A kinetic study of the effects of varying the phosphorus reagent and substituents in the nitro-compound in the reductivecyclisation of o-nitrobenzylideneamines to 2-substituted indazoles has been made. First-order rate constants vary from 8.2 to 52.2 × 10–5 s–1 for the triethyl phosphite-induced reduction of N-o-nitrobenzylideneanilines [o-NO2C6H4CHNC6H4Y; Y =p-MeO, p-Me, H, p-CI, p-Br, p-CO2Et, p-CN
动力学研究了在邻硝基亚苄基胺还原成2-取代的吲唑的环化反应中改变硝基化合物中磷试剂和取代基的作用。一级速率常数从8.2变化至52.2×10 -5小号-1为的亚磷酸三乙酯诱导的减少ñ - ö -nitrobenzylideneanilines [ ø -NO 2 ç 6 ħ 4 CH NC 6 H ^ 4 ÿ; Y = p -MeO,p -Me,H,p -Cl,p -Br,p -CO 2等等,p -CN。p -NO 2,或ö ] -CI和Ñ -5-氯-2- nitrobenzylideneaniline,并略有不同的5至6×10 -5小号-1为ö -nitrobenzylideneamines [ ø -NO 2 ·C 6 H ^ 4 · CH NR; R = Me中,乙基,丙基我,或卜Ñ ]。这些反应的产物是相应的2-芳基-(芳基= C 6 H 4 Y)和2-烷基-(烷基= R)-吲唑。这
Electrochemical Radical–Radical Cross-Coupling Approach between Sodium Sulfinates and 2<i>H</i>-Indazoles to 3-Sulfonylated 2<i>H</i>-Indazoles
作者:Wansoo Kim、Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.0c02144
日期:2020.8.21
A direct cross-coupling between sodium sulfinates and 2H-indazoles has been developed under electrochemical conditions. The utilization of a graphite anode and platinum cathode in an undivided cell with a constant current of 7 mA allowed the concurrent oxidations of sulfinates and 2H-indazoles to sulfonyl radical and radical cationic 2H-indazoles, facilitating the direct radical–radical coupling strategy
A general and practical method for the direct C–H amination of 2H-indazoles with a series of amines including aliphatic primary amines, secondary amines, azoles, and sulfoximines via organophotoredox-catalyzed oxidative coupling has been disclosed at room temperature under ambient air conditions. Additionally, this protocol is used for free aminated 2H-indazole synthesis. A mechanistic study revealed
Bu<sub>4</sub>NI-catalyzed, oxidative C<sub>(sp2)</sub>–C<sub>(sp3)</sub> cross dehydrogenative coupling for the regioselective direct C-3 benzylation of 2<i>H</i>-indazoles
作者:Lalit Yadav、Sandeep Chaudhary
DOI:10.1039/d0ob01282c
日期:——
A Bu4NI-catalyzed, DTBP-promoted, regioselective C(sp2)–C(sp3) cross dehydrogenative coupling (CDC) protocol for the direct C-3 benzylation of 2H-indazoles is reported. The metal-free protocol is operationally simple and proceeds mechanistically via the generation of stable benzylic free-radicals followed by regioselective addition at the C-3 position of 2H-indazoles which afforded C-3 benzylated 2H-indazoles
报道了一种 Bu 4 NI 催化、DTBP 促进的区域选择性 C (sp 2 ) -C (sp 3 )交叉脱氢偶联 (CDC) 方案,用于 2 H-吲唑的直接 C-3 苄基化。无金属方案操作简单,通过产生稳定的苄基自由基,然后在 2 H-吲唑的 C-3 位置进行区域选择性加成,得到 C-3 苄基化的2H-吲唑的产率高达 87%。该方法显示出一系列不同的官能团耐受性和广泛的底物兼容性。克级合成进一步突出了这种方法的重要性和通用性。