Abstract A new method for the synthesis of 3-thioazaspiro[4,5]trienones was developed using Pd nanoparticle catalysts, which are highly efficient, environmentally friendly and recyclable. Alkynes and thiophene phenols are effectively cyclized by Pd/ZrO2 catalyst under visible light irradiation. The present protocol simply utilizes visible light as the safe and ecofriendly energy source, and the Pd/ZrO2
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
Electrophilic <i>ipso</i>-Halocyclization
of <i>N</i>-Arylpropynamides with Polyfluoroalkyl
Alcohols: Selective Synthesis of 8-(Polyfluoroalkoxy)azaspiro[4.5]trienes
作者:Zhi-Qiang Wang、Bo-Xiao Tang、Hong-Ping Zhang、Feng Wang、Jin-Heng Li
DOI:10.1055/s-0028-1087972
日期:——
polyfluoroalkyl alcohols. In the presence of N-halosuccinimides (NXS), a variety of N-arylpropynamides underwent an electrophilic ipso-halocyclization reaction with polyfluoroalkyl alcohols to afford the corresponding 8-(polyfluoroalkoxy)spiro[4.5]trienes in good yields. Note that molecular sieves can improve the yield of the reaction. electrophilic ipso-halocyclization - N-arylpropynamide - N-halosuccinimide
A visiblelight‐induced (blue LED) radical cascade has been devised to effect selenylative spirocyclization of N‐aryl alkynamides at room temperature under oxygen atmosphere and without the aid of external photocatalyst. The protocol is operationally simple, scalable, and offers clean synthesis of 3‐selenospiro[4,5]trienones in high yields (up to 92%). A novel spiro‐ring‐opening strategy has also been
highly efficient palladium-catalyzedsynthesis of unsymmetrically substituted 3-(diarylmethylenyl)indolinones from readily accessible starting materials is developed. The domino reaction involves a sequence of intermolecular carbopalladation, C-H activation, and C-C bond formation. A plausible mechanistic pathway for the reaction is discussed on the basis of the kinetic isotope effect [K(H)/K(D) (intermolecular)