Tandem Double [3 + 2] Cycloaddition Reactions at Both C‑1 and C‑3 Atoms of <i>N</i>‑Cyanomethylisoquinolinium Ylide
2017-11-13T09:13:41Z (GMT) by
The base-promoted cycloaddition reaction of <i>N</i>-cyanomethylisoquinolinium chloride with 2-arylidene-1,3-indanediones in dry tetrahydrofuran resulted in the expected spiro[indene-2,1′-pyrrolo[2,1-<i>a</i>]isoquinoline] derivatives. However, the triethylamine-promoted three-component reaction of <i>N</i>-cyanomethylisoquinolinium chloride, aromatic aldehydes, and two molecules of 1,3-indanediones in acetonitrile afforded unique spiro[benzo[<i>f</i>]imidazo[5,1,2-<i>cd</i>]indolizine-4,2′-indene] derivatives in satisfactory yields through tandem double [3 + 2] cycloaddition reactions.
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