A tandem Michael addition/carbocyclization of 3,4-dimethoxyphenethyl maleimide with carbon and sulfur nucleophiles is accomplished via a relay catalysis using γ-Al 2 O 3 /TfOH binary system. The X-ray Photoelectron Spectroscopy (XPS) analysis of binary system indicates the presence of AlF 3 , 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 γ-Al 2 O 3 /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 AlF 3 , AlO(OH) species from γ-Al 2 O 3 and TfOH, which might have delineated the disadvantageous background reactions usually displayed by a strong Brønsted acid such as TfOH.
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