Anchored Palladium Complex‐Generated Clusters on Zirconia: Efficiency in Reductive N‐Alkylation of Amines with Carbonyl Compounds under Hydrogen Atmosphere. Issue 7 (9th March 2022)

• Record Type: Journal Article
• Authors: Zhang, Zhenzhong; Ikeda, Takuya; Murayama, Haruno; Honma, Tetsuo; Tokunaga, Makoto; Motoyama, Yukihiro
• Is Part Of: Chemistry, an Asian journal. Volume 17:Issue 7(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-09
• Subjects: alkylation -- amines -- cluster compounds -- heterogeneous catalysis -- palladium; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.202101243
• Languages: English
• ISSNs: 1861-4728

Abstract

Abstract: Carbon‐nitrogen bond formation is an important method on both laboratory and industrial scales because it realizes the production of valuable pharmaceuticals, agrochemicals, and fine chemicals. Direct reductive N ‐alkylation of amines with carbonyl compounds via intermediary imine compounds, especially under catalytic hydrogenation conditions, is one of the most convenient, economical, and environmentally friendly methods for this process. Here we report a novel palladium species on zirconia having specific activity towards hydrogenation of imines but other carbonyl groups remaining intact. The present catalytic property offers a practical synthetic method of functionalized secondary amines by reductive N ‐alkylation under mild conditions with high atom‐efficiency. Mechanistic studies revealed that the catalytically active species is the palladium cluster, which is generated in situ from molecular palladium complexes on the support by exposure to atmospheric hydrogen. These fundamental findings are expected to progress in developing novel cluster catalysts for chemical processes directed towards a sustainable society. Abstract : A facile generation method of palladium clusters and catalytic reductive N ‐alkylation of amines with carbonyl compounds are reported. The active Pd species are formed by treatment of highly dispersed molecular palladium complexes with atmospheric hydrogen, and the present catalyst system shows a broad substrate scope and functional group tolerance with respect to both amines and carbonyl compounds.