Photoisomerization and Photocyclization of 5-Styryloxazole
摘要:
This paper describes the competition of the relaxation processes (fluorescence, isomerization and cyclization) of 5-styryloxazole in the first excited singlet state. The study is carried out under mild conditions and in the first stage of irradiation to compare the photobehaviour with that reported in a previous work on preparative scale. The quantum yields of the radiative and reactive deactivation are compared with those of the analogous compounds containing pentatomic heteroaryl groups.
methods for the introduction of CF2H into heteroarenes. Herein we disclose a new strategy for the direct introduction of a difluoromethyl group into heteroarenes via the copper-mediated C-H oxidative difluoromethylation of heteroarenes with TMSCF2H. This mild and regioselective method enables the convenient synthesis of a range of difluoromethylated heteroarenes in high yields. The usage of 9,10-phenanthrenequinone
Pd/Cu-Catalyzed C–H/C–H Cross Coupling of (Hetero)Arenes with Azoles through Arylsulfonium Intermediates
作者:Ze-Yu Tian、Zeng-Hui Lin、Cheng-Pan Zhang
DOI:10.1021/acs.orglett.1c01322
日期:2021.6.4
A highly efficient method for the selective formal C–H/C–H cross-coupling of azoles and (hetero)arenes was established through arylsulfonium intermediates under transition-metal catalysis, which produced a variety of 2-(hetero)aryl azoles in good to excellent yields. Advantages of the reaction included mildness, a good functional group tolerance, a wide range of substrates, a high regio- and chemoselectivity
Rhodium/Copper Cocatalyzed Highly <i>trans</i>-Selective 1,2-Diheteroarylation of Alkynes with Azoles via C–H Addition/Oxidative Cross-Coupling: A Combined Experimental and Theoretical Study
作者:Guangying Tan、Lei Zhu、Xingrong Liao、Yu Lan、Jingsong You
DOI:10.1021/jacs.7b07242
日期:2017.11.8
experimental and theoretical methods, the reaction mechanism for addition/oxidative cross-coupling of internal alkynes with azoles has been investigated. Theoretical calculations reveal that the metalation/deprotonation of azole could occur with either rhodium or copper species. When azolylrhodium is formed, an alkyne could insert into the Rh–C bond. Another azolyl group could then transfer to rhodium from azolylcopper
A matter of catalyst: Azole compounds can be directly alkylated with N‐tosylhydrazones that bear unactivatedalkylgroups (see scheme; phen=1,10‐phenanthroline, Ts=p‐toluenesulfonyl). Nickel catalysis enables the introduction of simple secondary alkyl chains into benzoxazole compounds, whereas the alkylation of 5‐aryloxazoles and benzothiazole is possible by using a cobalt catalyst.
A copper-mediateddehydrogenative C–H/C–H biaryl coupling of phenols and 1,3-azoles has been developed. The key to its success is the introduction of a bipyridine-type bidentate auxiliary, 4,4′-di(tert-butyl)-2,2′-bipyridine, on the phenol oxygen, which is readily prepared and easily attachable, detachable, and recyclable. The reaction proceeds smoothly in the presence of copper salt alone to form