Visible-light-mediated selective thiocyanation/ipso-cyclization/oxidation cascade for the synthesis of thiocyanato-containing azaspirotrienediones
作者:Yuan Chen、Yu-Jue Chen、Zhi Guan、Yan-Hong He
DOI:10.1016/j.tet.2019.130763
日期:2019.12
visible-light-mediated metal-free thiocyanate radicaladdition/ipso-cyclization/oxidation cascade reaction for the synthesis of thiocyanato-containing azaspirotrienediones from N-phenylpropynamides is described. Cheap and readily available ammonium thiocyanate was used as a precursor to the thiocyanate freeradical, which undergoes a radicaladditionreaction with the alkyne, followed by selective ipso-cyclization
Copper-Catalyzed Difunctionalization of Activated Alkynes by Radical Oxidation-Tandem Cyclization/Dearomatization to Synthesize 3-Trifluoromethyl Spiro[4.5]trienones
A copper‐catalyzed difunctionalizing trifluoromethylation of activated alkynes with the cheap reagent sodium trifluoromethanesulfinate (NaSO2CF3 or Langlois’ reagent) has been developed incorporating a tandem cyclization/dearomatization process. This strategy affords a straightforward route to synthesis of 3‐(trifluoromethyl)‐spiro[4.5]trienones, and presents an example of difunctionalization of alkynes
Transformations of N-arylpropiolamides to indoline-2,3-diones and acids via C≡C triple bond oxidative cleavage and C(sp2)–H functionalization
作者:Ming-Bo Zhou、Yang Li、Xuan-Hui Ouyang、Jin-Heng Li
DOI:10.1007/s11426-019-9633-x
日期:2020.2
A new palladium-catalyzed oxidative conversion of N-arylpropiolamides and H2O to various indoline-2,3-diones and acids through the C≡C triple bond cleavage and C(sp2)–H functionalization is described, which is promoted by a cooperative action of catalytic CuBr2, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and O2. The method provides a practical tool for transformations of alkynes by means of a C–H
Silver-catalyzed direct spirocyclization of alkynes with thiophenols: a simple and facile approach to 3-thioazaspiro[4,5]trienones
作者:Huanhuan Cui、Wei Wei、Daoshan Yang、Jimei Zhang、Zhihong Xu、Jiangwei Wen、Hua Wang
DOI:10.1039/c5ra16548b
日期:——
A new and convenient silver-catalyzed direct oxidative spirocyclization of alkynes with thiophenols is described. This methodology provides a simple and practical approach to various 3-thioazaspiro[4,5]trienones in moderate to good yields with high atom efficiency and excellent functional group tolerance.
Access to 3‐(2‐Oxoalkyl)‐azaspiro[4.5]trienones
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Acid‐Triggered Oxidative Cascade Reaction through Alkenyl Peroxide Radical Intermediate
作者:Chang‐Sheng Wang、Thierry Roisnel、Pierre H. Dixneuf、Jean‐François Soulé
DOI:10.1002/adsc.201801203
日期:2019.2
Azaspiro[4.5]trienones bearingketone side chains at the 3‐position are prepared from N‐alkyl‐arylpropiolamides and ketones via oxidative 1,2‐difunctionalization of alkynes. The cascade sequence starts with the generation of alkenyl peroxide intermediates, which are obtained by addition of tert‐butyl hydroperoxide to ketones in presence of a catalytic amount of a strong acid. Then, the ketone radical adds to