Photoinduced and N-Bromosuccinimide-Mediated Cyclization of 2-Azido-N-phenylacetamides
摘要:
An efficient synthesis of quinoxalin-2(1H)-ones or spiro[cyclohexene-1,2'-imidazol]-4'-cones has been achieved in moderate to high yields by the visible light-induced and N-bromosuccinimide-mediated cyclization reaction of 2-azido-N-phenylacetamides at ambient temperature. Both the regioselectivity and the speed of cyclization are affected by the substituents attached to the phenyl ring. For example, quinoxalin-2-ones are produced as the main products when the substrates bear electron-withdrawing groups at the para-position of the phenyl ring; in contrast, spiro[cyclohexene-1,2'-imidazol]-4'cones are obtained as the main products when the substrates bear electron-donating groups at the para-position.
<i>O</i>-Perfluoropyridin-4-yl Oximes: Iminyl Radical Precursors for Photo- or Thermal-Induced N–O Cleavage in C(sp<sup>2</sup>)–C(sp<sup>3</sup>) Bond Formation
作者:Peng-Ju Xia、Yuan-Zhuo Hu、Zhi-Peng Ye、Xu-Jie Li、Hao-Yue Xiang、Hua Yang
DOI:10.1021/acs.joc.9b03251
日期:2020.3.6
group was first installed onto cycloketone oximes as a new electrophore, which was proven to be efficient iminyl radicalprecursors under photocatalytic and thermal conditions. A range of O-perfluoropyridin-4-yl oximes were successfully utilized in C(sp2)-C(sp3) bond formations of quinoxalin-2(1H)-ones and alkenes, providing facile accesses to a range of functionalized alkylnitriles.
Visible-light-induced C H arylation of quinoxalin-2(1H)-ones in H2O
作者:Hanyang Bao、Ziyun Lin、Mengshi Jin、Hongdou Zhang、Jun Xu、Bajin Chen、Wanmei Li
DOI:10.1016/j.tetlet.2021.152841
日期:2021.3
An efficient visible-light-induced CH arylation of quinoxalin-2(1H)-ones in H2O is developed, which has the advantages of mild reaction conditions, environmental friendliness and good functional group tolerance. This strategy provides a simple operation method to access various 3-aryl quinoxalin-2(1H)-ones in moderate to good yields.
An efficient synthesis of cyanoalkylated heteroarenes via iron-catalyzed direct C–Hcyanoalkylation of heteroarenes has been developed. Structurally diverse cyanoalkyl motifs generated throughC–C bond cleavage of cyclobutanone oxime esters have been introduced into quinoxalin-2(1H)-ones, flavone, benzothiazoles, and caffeine in good to excellent yields. Remarkably, less-strained cyclopentanone and
Various 3‐alkoxylated quinoxalin‐2(1H)‐ones were synthesized in a simple undivided cell via electrochemically dehydrogenative C–H/O–H cross‐coupling between quinoxalin‐2(1H)‐ones and alcohols under mild conditions.
Visible‐Light Photoredox Catalyzed C−N Coupling of Quinoxaline‐2(1
<i>H</i>
)‐ones with Azoles without External Photosensitizer
作者:Mingli Sun、Lei Wang、Lulu Zhao、Zhiming Wang、Pinhua Li
DOI:10.1002/cctc.202000459
日期:2020.10.20
A visible‐lightphotoredoxcatalyzedC−Ncoupling of quinoxaline‐2(1H)‐ones with azoles in the absence of externalphotosensitizer has been developed. The protocol employs commercially available pyrazoles and triazoles as amination reagents and shows wide substrate scope, providing the corresponding C3‐position amination products in good yields and high regioselectivity under ambient conditions. Investigations
在没有外部光敏剂的情况下,已经开发了可见光的光氧化还原催化喹喔啉-2(1 H)-one与唑类的C-N偶联。该方案使用了市售的吡唑和三唑作为胺化试剂,并显示了较宽的底物范围,可在环境条件下以高收率和高区域选择性提供相应的C3位胺化产物。研究表明,原料和产物可以用作光敏剂,避免以自催化方式使用其他光催化剂。另外,1 O 2与分子氧中的O 2 .-共存(3 O 2)通过反应过程中的能量转移(ET)和单电子转移(SET)过程。