An iron-catalysed hydrosilylation of ketones

Abstract

The combination of Fe(OAc)2 and multi-nitrogen-based ligands such as N,N,N',N'-tetramethyethylenediamine, bis-tert-butyl-bipyridine, or bis(oxazolinyl)pyridine can efficiently catalyse hydrosilylation of ketones to give the corresponding alcohols in high yields including asymmetric catalysis.

Iron Dihydride Complex as the Pre‐catalyst for Efficient Hydrosilylation of Aldehydes and Ketones Under Visible Light Activation

“…Electrondeficient as well as electron-donating groups on the aryl ring did not show any significant influence on the activity of the iron catalyst. Interestingly, functional groups such as CN, Br remained unchanged under such reaction conditions ( Table 2, entries [8][9][10].…”

“…In contrast to aldehydes, aryl methyl ketones bearing substituents in the ortho-position of the aryl ring led to the corresponding alcohols in 68-99% isolated yield, which shows that ortho hindered substituents can hamper the reaction (Table 3, entries 2/3 and 4/6). The hydrosilylation reaction was suitable to both electron-rich and electron-poor substituted (Me, OMe N-morpholinyl, Br) aromatic methyl ketones, and the reaction gave the corresponding alcohols in good to excellent yields (68-99%; Table 3, entries [1][2][3][4][5][6][7][8]. The principle of this iron-catalyzed transformation can also be extended to heterocyclic methyl ketones such as 2-pyridyl methyl ketone (Table 3, entry 11), to a-tetralone (Table 3, entry 12) or to benzophenone derivatives such as 4,4'-dimethylbenzophenone (Table 3, entry 13).…”

“…The first one, mainly developed by Beller and Nishiyama, is based on the use of iron salts [often FeA C H T U N G T R E N N U N G (OAc) 2 in situ associated with nitrogen, phosphine or thiophene ligands] to prepare efficient catalysts for the hydrosilylation of carbonyl derivatives. [8] Typically, 5 mol% of iron salt associated with 10 mol% of ligand at 65 8C for 16 h are used to perform such reactions, and they could be adapted for asymmetric versions. [9] The other hydrosilylation approach was based on well-defined iron complexes as pre-catalysts: the pioneering Brunner CpFe(CO) 2 R system, [10] Gade bis(pyridylimino)isoindole pincer iron(II) catalyst, [11] or Nikonov CpFe(II)phosphinebased complex.…”

Zinc Acetate‐Catalyzed Enantioselective Hydrosilylation of Ketones

“…[2] Recently,e nvironmentally benign and less expensive catalysts have also been exhaustively exploredl eading to broad acceptance of earth-abundant metals such as zinc [3] and iron [4] in asymmetric synthesis. Particularly stimulating progress has been observed recently in the asymmetric hydrosilylation of ketones promoted by ironc omplexes.S ince Nishiyama [5] and Beller [6] reported the first examples of Fe(OAc) 2 -catalyzed asymmetric hydrosilylation with (EtO) 2 MeSiH and (EtO) 3 SiH, manyi ron-based catalysts have been studied for the asymmetric hydrosilylation of ketones.[7] However, ironc omplexes are often sensitive to the reactionc onditions due to the easy oxidation of iron(II)a nd also require relatively elevatedt emperatures. Only recently, an example of am ore reactive and enantioselective iron complex with the boxmi ligand has been presented by Gade.…”

TMEDA: Efficient and Mild Catalyst for the Acylation of Alcohols, Phenols and Thiols under Solvent-free Condition

“…7 Nishiyama et al have shown that TMEDA acts as a powerful ligand for the hydrosilylation of ketones. 8 TMEDA also promotes regioselective ring opening of aziridines with trimethylsilylated nucleophiles. 9 Sano et al 10 demonstrated that TMEDA could induce the acylation of alcohol with benzoyl chloride.…”