Tantallaaziridines: from synthesis to catalytic applications

Tantallaaziridines are a class of organometallic compounds containing three-membered rings that include a tantalum, carbon and nitrogen atom. Closely related complexes containing the related iminoacyl ligand can be used as starting materials for tantallaaziridine synthesis. Tantallaaziridines can also be synthesized by reduction of imines or beta-hydrogen abstraction of amides to give stable, isolable complexes. Tantallaaziridines possess a reactive Ta-C bond that can undergo stoichiometric transformations with unsaturated organic molecules to give new organometallic products. Upon quenching of such reactions with aqueous workup, selectively substituted small molecule amines can be prepared. Tantallaaziridines have also been proposed as catalytic intermediates in the direct alpha-alkylation of amines, hydroaminoalkylation, by exploiting the beta-hydrogen abstraction route to regenerate the catalytically active species. Recent progress and remaining challenges in the field will be discussed.