Copper-Catalyzed Multicomponent Synthesis of Fluorescent 2-Phenyl-1′H-spiro[fluorene-9,4-naphtho[2′,3-h]quinoline]-7′,12′-dione Derivatives

Copper-catalyzed multicomponent coupling reactions between ketones, alkynes, and amines (KA(2) coupling) by using 9-fluorenones 1a-1e, aryl alkynes 2a-2g, and amino anthraquinones 3a and 3b afforded the highly conjugated, fluorescent spirofluorenonaphthoquinoline derivatives 4a-4r in very good yields. The products obtained from 1-aminoanthraquinone (3a) and 1,4-diaminoanthraquinone (3b) appear different in color but both series of products show emission in the red region. An analogous reaction with 1-aminopyrene (5) afforded the highly fluorescent hybrid pyrene-fluorenone spirocycle derivative 6, which shows emission in the deep blue region.