Soluble aluminum hydrides function as catalysts in deprotonation, insertion, and activation reactions

The past decades have witnessed staggering progress in the chemistry of compounds with s- and p-block elements. Aluminum compounds, especially soluble aluminum hydrides, received wide explorations due to their high reactivity towards protonic reagents and unsaturated compounds containing multiple bonds such as C[dbnd]O, C[dbnd]NR, C[tbnd]N, and C[tbnd]C. Recent studies suggest that reactions employed aluminum hydrides usually occurred via deprotonation or hydroalumination, which exhibit great perspective in main group catalysis. These stoichiometric reactions often act as the initial step during the overall catalytic cycle. Appropriate ligands at the central Al atom are important for the activation of the substrates and the regeneration of the active catalytic molecules. In this review, we focus on the activation of carbonyl compounds, alkenes, and alkynes using soluble aluminum hydrides based on the previous stoichiometric reactions. Different mechanisms were proposed to explain the driving force for the turnover of the catalytic cycle in dehydrocoupling, hydroboration, and hydrosilylation. Moreover, aluminum hydrides stabilized by tridentate ligands, which function in the dehydrocoupling of benzylamine and dehydrogenation of formic acid, are also included in this review.