Imido complexes of early transition metals are key intermediates in the synthesis of many nitrogen-containing organic compounds. The metal—nitrogen double bond of the imido moiety undergoes [2+2] cycloaddition reactions with various unsaturated organic molecules to form new nitrogen—carbon and nitrogen—heteroatom bonds. This review article focuses on reactivity of the terminal imido complexes of Group 4–6 metals, summarizing their stoichiometric reactions and catalytic applications for a variety of reactions including alkyne hydroamination, alkyne carboamination, pyrrole formation, imine metathesis, and condensation reactions of carbonyl compounds with isocyanates.

早期过渡金属的酰亚胺配合物是合成许多含氮有机化合物的关键中间体。亚氨基部分的金属-氮双键与各种不饱和有机分子发生[2+2]环加成反应，形成新的氮-碳键和氮-杂原子键。本文重点关注第 4-6 族金属的末端亚氨基配合物的反应性，总结了它们的化学计量反应和在各种反应中的催化应用，包括炔烃氢胺化、炔烃碳胺化、吡咯形成、亚胺复分解以及羰基化合物与异氰酸酯。