Benzimidazole fragment containing Mn-complex catalyzed hydrosilylation of ketones and nitriles. Issue 37 (11th September 2020)

• Record Type: Journal Article
• Authors: Ganguli, Kasturi; Mandal, Adarsha; Sarkar, Bidisha; Kundu, Sabuj
• Is Part Of: Tetrahedron. Volume 76:Issue 37(2020)
• Publication Date: 2020-09-11
• Subjects: Benzimidazole -- Mn(I) complex -- Hydrosilylation -- Nitriles -- Ketones; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2020.131439
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The synthesis of a new bidentate (NN)–Mn(I) complex is reported and its catalytic activity towards the reduction of ketones and nitriles is studied. On comparing the reactivity of various other Mn(I) complexes supported by benzimidazole ligand, it was observed that the Mn(I) complexes bearing 6-methylpyridine and benzimidazole fragments exhibited the highest catalytic activity towards monohydrosilylation of ketones and dihydrosilylation of nitriles. Using this protocol, a wide range of ketones were selectively reduced to the corresponding silyl ethers. In case of unsaturated ketones, the chemoselective reduction of carbonyl group over olefinic bonds was observed. Additionally, selective dihydrosilylation of several nitriles were also achieved using this complex. Mechanistic investigations with radical scavengers suggested the involvement of radical species during the catalytic reaction. Stoichiometric reaction of the Mn(I) complex with phenylsilane revealed the formation of a new Mn(I) complex. Graphical abstract: Image 1 Highlights: Synthesis and characterization of nitrogen containing bidentate Mn(I) complexes. Investigating the catalytic activity of synthesized Mn(I) complexes towards the hydrosilylation of ketones. This is the first report of base free Mn(I) complex catalyzed dihydrosilylation of nitriles. Mechanistic studies revealed the intermediacy of radical species.