C-3 alkylation of oxindole with alcohols catalyzed by an indene-functionalized mesoporous iridium catalyst

A heterogeneous indene-based iridium catalyst with a highly ordered dimensional-hexagonal mesostructure was prepared through complexation of IrCl3 with the indene-functionalized SBA-15 silica materials. During C-3 alkylation of oxindole with various alcohols, this heterogeneous catalyst exhibited highly catalytic activity (up to 93%). Such a catalyst could be recovered easily and used repetitively eight times without significantly affecting its catalytic activity.

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► A facile preparation of a mesoporous silica-supported iridium catalyst with a highly ordered dimensional-hexagonal mesostructure was developed.
► This catalyst exhibited high catalytic activity in C-3 alkylation of oxindole, in which alcohols as alkylative reagents were environmentally friendly and the mesoporous materials as a catalyst could be recycled.
► In eight consecutive reactions, the recycling catalyst still afforded high catalytic activity, showing good potential in the industrial application.