Synthesis of Benzofuran Derivatives by Diphenylperhydroindolinol Silyl Ether-Catalyzed Asymmetric [3+3] Aza-cyclization ofα,β-Unsaturated Aldehydes

Synthesis, structural characterization, and coordination chemistry of imidazole-based alkylidene ketenes

Alkylidene ketenes typically display high intrinsic reactivity, impeding isolation on a preparative scale. Herein, we report the synthesis of alkylidene ketenes by reaction of imidazole-based diazoolefins with carbon monoxide. The good thermal stability of these heterocumulenes allows for characterization by single crystal X-ray diffraction. N-Heterocyclic alkylidene ketenes can be used as C-donor ligands for transition and main group metals, as evidenced by the isolation of complexes with AuCl, RhCl(CO)₂, PdCl(C₃H₅) and GaCl₃.