01880nas a2200277 4500008004100000022001400041245020500055210006900260260000800329300001400337490000700351520083000358653002201188653003201210653001301242653002101255653003501276653002101311653001401332100002801346700001801374700002401392700002101416700003601437856012901473 2021 eng d a0022-152X00agamma-Al2O3/triflic acid as cooperative catalysts for the tandem Michael addition/carbocyclization: an easy access to 2-substituted pyrrolo[2,1-a]isoquinolines and 3-substituted pyrrolidine-2,5-diones0 agammaAl2O3triflic acid as cooperative catalysts for the tandem M cJUL a1415-14280 v583 a
A tandem Michael addition/carbocyclization of 3,4-dimethoxyphenethyl maleimide with carbon and sulfur nucleophiles is accomplished via a relay catalysis using gamma-Al2O3/TfOH binary system. The X-ray Photoelectron Spectroscopy (XPS) analysis of binary system indicates the presence of AlF3, AlO(OH) species(.) This approach provides an easy access to 2-aryl or 2-thio aryl pyrrolo[2,1-a]isoquinolines in good yields in a tandem fashion. With suitable ratio of gamma-Al2O3/TfOH binary system, the Michael addition of N/C/S nucleophiles to N-benzyl maleimide is also achieved. A key to the success of these reactions would be the generation of AlF3, AlO(OH) species from gamma-Al2O3 and TfOH, which might have delineated the disadvantageous background reactions usually displayed by a strong Bronsted acid such as TfOH.
10a1-a]isoquinolines10a3-substituted pyrrolidine-210a5-diones10acarbocyclization10agamma-Al2O3/TfOH binary system10aMichael addition10apyrrolo[21 aRao, Ramana, Sreenivasa1 aSahani, Anita1 aAli, Sheikh, Haider1 aPradhan, Sumanta1 aRamanathan, Chinnasamy, Ramaraj uhttp://library.ncl.res.in/content/gamma-al2o3triflic-acid-cooperative-catalysts-tandem-michael-additioncarbocyclization-easy