Molecular diversity of acid-catalyzed one-pot reaction of arylamines, methyl propiolate, and isatins.

Under the catalysis of p-TsOH, ß-enamino esters, generated in situ from the reaction of arylamines and propiolate, were reacted with isatins to afford isatinylidene bis(3-arylamino)acrylates in moderate yields. When BF3·OEt2 was used as catalyst, similar reactions of the in situ generated ß-enamino esters resulted in the corresponding spiro[indoline-3,4'-pyridine] derivatives in good yields.