Hydrodeoxygenative Coupling and Transformation of Aldehydes at a N 2 -Derived Tetranuclear Titanium Imide/Hydride Framework.

Carbon-carbon bond formation via coupling of two organic components is among the most important chemical transformations in organic synthesis. Herein, we report an unprecedented hydrodeoxygenative coupling of aromatic aldehydes to form bibenzyls by a N 2 -derived tetranuclear titanium imide/hydride complex [(Cp'Ti) 4 (μ 3 -NH) 2 (μ-H) 4 ] ( 1 ; Cp' = C 5 Me 4 SiMe 3 ). Further reactions with the corresponding aldehydes under air afford hydrobenzamides together with a titanium oxo complex. Both hydride and imide ligands play an important role for the reductive coupling, hydrogenation processes, as well as the functionalization of the N 2 -derived imide units without the need of sacrificial reagents. These results demonstrate that the tetranuclear titanium imide/hydride framework is not only applicable for N 2 activation and functionalization but also providing a new platform for the C-C bond formation using carbonyl compounds.