Organoaluminum cations for carbonyl activation

In search of stable, yet reactive aluminum Lewis acids, we have isolated an organoaluminum cation, [(Me2NC6H4)(2)Al(C4H8O)(2)](+), coordinated with two labile tetrahydrofuran ligands. Its catalytic performance in aldehyde dimerization reveals turn-over frequencies reaching up to 6000 h(-1), exceeding that of the reported main group catalysts. The cation is further demonstrated to catalyze hydroelementation of ketones. Mechanistic investigations reveal that aldehyde dimerization and ketone hydrosilylation occur through carbonyl activation.