Synthesis of Highly Functionalized Spirocycles and Pentafulvene-Containing Dyes Involving 2-(2'-ketoalkyl)-1,3-indandiones.

Synthesis of highly functionalized spiro[4.4]nonane and spiro[4.5]decane motifs by the reaction of dimethylacetylenedicarboxylate (DMAD) with 2-(2'-ketoalkyl)-1,3-indandiones and 2-(3'-ketoalkyl)-1,3-indandiones, respectively, has been developed by utilizing a catalytic amount of DABCO.