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 Rong-Guo Shi Jing Sun Chao-Guo Yan
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.