TiO2–silica mediated one pot three component 1,3-dipolar cycloaddition reaction: a facile and rapid synthesis of dispiro acenaphthenone/oxindole [indanedione/oxindole] pyrroloisoquinoline ring systems

TiO2–silica is used as an efficient solid-supported catalyst for the synthesis of a series of novel dispiroheterocyclic systems by the cycloaddition of an azomethine ylide generated by the decarboxylative route from tetrahydroisoquinoline-3-carboxylic acid and acenaphthenequinone/isatin with various unusual dipolarophiles such as 2-arylidene-1,3-indanediones and (E)-2-oxoindolino-3-ylidene acetophenones in a one pot three component tandem reaction, in moderate to good yields. The regiochemistry and stereochemistry of the title compound were established by spectroscopic techniques.