Dinitrogen (N2) functionalization with carbon building blocks to construct complex carbon-nitrogen architectures under mild conditions represents a long-standing challenge of fundamental interest and practical importance. Here, we report an unprecedented functionalization of dinitrogen via multicoupling with allene, isocyanide, and carbon monoxide (CO) enabled by a dititanium platform. Reaction of the dinitrogen/oxymethylene complex (acriPNP) Ti2 (μ-η1: η2-N2) (μ-η1: η2-OCH2) (1), formed from (acriPNP) Ti2 (H) (μ-H) 3, N2 and CO, with phenylallene (PhCH=C=CH2) at room temperature, selectively affords a phenylpropenylhydrazido/formyl complex (acriPNPTi) 2μ-η1: η2-NNC (CH3) =CHPh (μ-η1: η2-CHO) (2). This transformation proceeds through the formation of N-C bonds between the N2 unit and the central carbon of the allene, followed by hydrogen migration from the oxymethylene ligand to the terminal carbon of the allene. Treatment of 2 with two equivalents of benzyl isocyanide furnishes a novel multicomponent coupling product (acriPNP) (O) Tiμ-κ2: κ5-CPh=CMeNNC (=NCH2Ph) CH=C (acriPNP) TiNHCH2Ph (4), accompanied by formyl deoxygenation and debenzylamination (C≡N bond cleavage) of one isocyanide molecule as well as C-P bond formation with a PNP ligand. A related multicomponent coupling product (acriPNP) (O) Tiμ-κ2: κ5-CHPhC (Me) =NN=C (NCH2Ph) CH=C (acriPNP) Ti=O (7) is obtained by sequential reaction of 2 with benzyl isocyanide (1. 0 equiv) and CO (1 atm). The mechanistic details of these transformations are elucidated by isotope-labeling experiments, isolation of key intermediate, and density functional theory (DFT) calculations. This work demonstrates the capacity of a dititanium framework to orchestrate integrated bond-forming and bond-cleaving events for multicomponent dinitrogen functionalization, providing a new strategy for assembling complex N-N-containing architectures directly from N2.
Zhou et al. (2026) studied this question.