The base-promoted cycloaddition reaction of N -cyanomethylisoquinolinium chloride with 2-arylidene-1,3-indanediones in dry tetrahydrofuran resulted in the expected spiro[indene-2,1′-pyrrolo[2,1- a ]isoquinoline] derivatives. However, the triethylamine-promoted three-component reaction of N -cyanomethylisoquinolinium chloride, aromatic aldehydes, and two molecules of 1,3-indanediones in acetonitrile afforded unique spiro[benzo[ f ]imidazo[5,1,2- cd ]indolizine-4,2′-indene] derivatives in satisfactory yields through tandem double [3 + 2] cycloaddition reactions.

The three-component reaction resulted in the unique spiro[indoline-3,4′-naphtho[1,2-b]furan] derivatives, which were converted to spiro[indoline-3,2′-naphthalen]-4′-yl acetates by acylation and alkoxy-substituted spiro[benzo[h]chromene-5,3′-indolines] by acid catalyzed etherification.

A unique [3 + 2]–[4 + 2]–[3 + 2] cycloaddition sequence of isoquinolinium ylide is investigated to afford polycyclic compounds with ten stereogenic centers.

A unique two-carbon ring expansion of isatin has been achieved to conveniently construct the functionalized dibenzo[b,d]azepin-6-one scaffold in moderate to high yields, and the two carbon sources are different: one carbon is from the N-substituent of pyridinium bromide and the other is from indene-1,3-dione.

Triethylamine promoted the pseudo-five-component reaction of aromatic aldehyde with four molecules of 1,3-indanediones in refluxing ethanol to give unique polycyclic bicyclo[2.2.2]­octane derivatives containing bridged- and spiro-indanone scaffolds in good yields. The mechanistic studies supported that the reaction included base-catalyzed cyclotrimerization of 1,3-indanedione to give an active cyclic diene and the sequential Diels–Alder reaction with in situ generated 2-arylidene-1,3-indanediones as electron-deficient dienophiles. On the other hand, the pseudo-four-component reaction of salicylaldehyde with 1,3-indanedione afforded the dibenzo­[b,g]­indeno­[1′,2′:3,4]­fluoreno­[1,2-d]­oxonines in high yields. This reaction clearly demonstrated the high efficiency, molecular convergence, atom-economy, and impressive selectivity of multicomponent reactions.