Polyoxometalate catalyzed imine synthesis: Investigation of mechanistic pathways. Issue 25 (19th June 2020)

• Record Type: Journal Article
• Authors: Adhikary, Subhasis D.; Mandal, Debaprasad
• Is Part Of: Tetrahedron. Volume 76:Issue 25(2020)
• Publication Date: 2020-06-19
• Subjects: Polyoxometalates -- Oxidative coupling -- Oxygen activation -- Selectivity -- Imines; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2020.131245
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The syntheses of imines by oxidative coupling of primary alcohols and amines were achieved by using 2 mol% polyoxometalate (POM) Na12 [WZn3 (H2 O)2 (ZnW9 O34 )2 ] (Zn–WZn3 ) catalyst in the presence of t- BuOK and di-oxygen with excellent conversion (up to 100%) and selectivity (up to 100%). Non-noble metal-based POM catalyst in the presence of base represents a new reaction protocol for the selective synthesis of imine from both aromatic and aliphatic primary amines with functional group tolerance. Control experiment shows the formation of di-oxygen bind Zn–WZn3 activated species. The electron-density of POM is mostly situated on the surface oxygen atoms of W–O–W bonds which can engage the alcoholic OH group and helps for the imine selectivity in the second step of imine synthesis. Graphical abstract: Image 1