TiO2-silica mediated one pot three component 1,3-dipolar cycloaddition reaction:: a facile and rapid synthesis of dispiroacenaphthenone/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. (C) 2007 Elsevier Ltd. All rights reserved.