带有N-苯基马来酰亚胺的2-(1'-环烯基)噻吩和2-(1'-环烯基)苯并[ b ]噻吩的Diels-Alder / Ene反应性:环烯环大小对苯并噻吩和二苯并噻吩产物分布的作用
摘要:
噻吩和苯并噻吩的支架是自然界中发现的丰富的生物活性化合物的重要类别。2-(1'-环烯基)噻吩和2-(1'-环烯基)苯并[ b ]噻吩的Diels-Alder反应具有在五个,六个,七个,八个和十二个烷基中存在的烯基N取代的成员环-苯基马来酰亚胺被表征。环烯环的大小在决定预期的和异构化的Diels-Alder加合物的产物分布中起着至关重要的作用。2D NMR研究表明,具有五,六和七元环的2-(1'-环烯基)噻吩的分离的异构体是芳构化的苯并噻吩产物,而八和十二元环是未重排的加合物。另外,对于五元和六元环的情况,分离出随后的与N-苯基马来酰亚胺的烯反应的产物。有趣的是,在2-(1'-环烯基)苯并[ b具有五元,六元,七元,八元和十二元环的]噻吩,在任何情况下均未分离未重排的二苯并噻吩Diels-Alder加合物。进行分子力学和密度泛函理论(M06-2X和PBE0-D3)的计算是为了了解各种二烯对于
An efficient copper-catalyzed radical ring-opening halogenation with HX (aq) is described. This protocol features redox-neutral conditions, green halogen sources, and a broad substrate scope, providing practical access to distally chlorinated, brominated and iodinated alkyl ketones and alkyl nitriles with moderate to good yields.
In-situ-generation of alkylsilyl peroxides from alkyl hydroperoxides and their subsequent copper-catalyzed functionalization with organosilicon compounds
Alkylsilyl peroxides were generated in situ from the corresponding alkyl hydroperoxides using organosilicon compounds of the type Me3SiX (X = CN, N3, and halogens) and an amine base. Subsequent in situ copper-catalyzed homolytic cleavage of the alkylsilyl peroxides afforded alkyl radicals, which were then trapped with X (X = CN, N3, and halogens) to furnish products with new carbon-carbon, carbon-nitrogen
Asymmetric Ketoalkylation/Rearrangement of Alkyenlfurans via Synergistic Photoredox/Brønsted Acid Catalysis
作者:Jie Wei、Yurong Tang、Qian Yang、Hongxiang Li、Dongxian He、Yunfei Cai
DOI:10.1021/acs.orglett.2c03040
日期:2022.11.4
An enantioselective three-component rearrangement of alkenylfurans with various cycloalkyl silyl peroxides and anilines has been developed by merging photoredox catalysis with chiral Brønstedacidcatalysis. This protocol provides expedient access to a broad spectrum of ketoalkyl-functionalized 4-aminocyclopentenones in high yields with excellent enantio- and diastereoselectivities. Diverse functional
Alkyl tert-butyl peroxides are prepared from the corresponding tert-alkyl precursors and tert-butyl hydroperoxide in the presence of a promoter. These substrates can be utilized in a mild copper-catalyzed radical functionalization that utilizes several coupling partners and has a broad substrate scope. A mechanistic study suggests that alkyl radical species participate in the coupling reactions.
Photophysical properties of thiophenes and 2,2′-bithiophenes containing alicyclic moieties
作者:Violetta V. Meshkovaya、Alexander V. Yudashkin、Yuri N. Klimochkin
DOI:10.1016/j.dyepig.2014.09.013
日期:2015.2
A series of novel 1-hydroxycycloalkyl- and cycloalkenylthiophenes (4a-4c, 4e, 6b, 6d, 6e) and bithiophenes (5a-5e, 7b-7e) were synthesized via Grignard reaction. The conditions control in the Grignard reaction allowed to obtain tertiary alcohols or cycloalkenes selectively. The Vilsmeier-Haack formylation of thiophenes and 2,2'-bithiophenes with alicyclic fragment C-4-C-5 results formation of unsaturated aldehydes whereas cycloalkenes C-6 form 5'-formylbithiophenes as the main isomers. The photophysical properties such as absorption and fluorescence spectra were recorded in different solvents, and relative quantum yields of aldehydes (9a, 9b, 11c-11e) and corresponding carbonitriles (13a, 13b, 15c-15e) were measured. The synthesized compounds showed an intense fluorescence in the 400-520 nm range, moderate quantum yields and large Stokes' shifts values. (C) 2014 Elsevier Ltd. All rights reserved.