Hydrosilane Reduction of Nitriles to Primary Amines by Cobalt–Isocyanide Catalysts

Abstract

Reduction of nitriles to silylated primary amines was achieved by combination of 1,1,3,3-tetramethyldisiloxane (TMDS) as the hydrosilane and a catalytic amount of Co­(OPiv)2 (Piv = CO t Bu) associated with isocyanide ligands. The resulting silylated amines were subjected to acid hydrolysis or treatment with acid chlorides to give the corresponding primary amines or imides in good yields. One-pot synthesis of primary amides to primary amines with hydrosilanes was also achieved by iron–cobalt dual catalyst systems.

Efficient Cobalt Catalyst for Ambient-Temperature Nitrile Dihydroboration, the Elucidation of a Chelate-Assisted Borylation Mechanism, and a New Synthetic Route to Amides

“…Cobalt catalysts have been extensively utilized for hydride-transfer reactions including hydrogenation, ,,− hydrosilylation, ,,, and hydroboration − of unsaturated substrates. Only recently has their utility been extended to nitrile dihydroboration.…”

Rhodium-Catalyzed Chemoselective Hydrosilylation of Nitriles to an Imine Oxidation Level Enabled by a Pincer-type Group 13 Metallylene Ligand

“…One of challenging substrates in hydrosilylation reactions is a nitrile, which is usually less reactive than other carbonyl compounds and requires highly reactive transition metal catalysts . Another important issue in hydrosilylation of nitriles is chemoselectivity; monoaddition of a silane to a nitrile affords an N -silylimine as an initial product, which is usually more reactive than the nitrile and is easily converted to an N , N -disilylamine via the second addition of the silane. , Selective hydrosilylation of nitriles to an imine oxidation level has still remained challenging since such chemoselectivity and reactivity usually offset each other. Nikonov reported a Ru-catalyzed efficient hydrosilylation reaction of nitriles to N -silylimines with good functional group compatibility although the use of two equivalents of silanes resulted in the formation of N , N -disilylamines as products .…”

Catalytic Reduction of Nitriles by Polymethylhydrosiloxane Using a Phenalenyl-Based Iron(III) Complex

“…(Scheme ). − Boron-catalyzed reduction of nitriles was also reported using expensive silane Et 2 SiH 2 …”

“…In 1985, Murai and co-workers demonstrated that conversion of aromatic nitriles and few aliphatic nitriles into their corresponding amines is possible in the presence of Co 2 (CO) 8 as a catalyst. , In 2012, Beller and co-workers successfully achieved the reduction of aromatic and aliphatic nitriles using 10 mol % Fe­(OAc) 2 and 20 mol % free ligand as the catalyst combination in the presence of an expensive hydrosilane (OEt) 2 MeSiH at 100 °C . Nakazawa’s group reported an iron-complex-catalyzed reduction of nitrile to their corresponding amines requiring an excess amount of nitrile, which is considered as a drawback for scaling up the synthesis of amine industrially. , Recently, Nagashima and co-workers successfully reduced nitriles to primary amines using tetramethyldisiloxane (TMDS) as the hydride source and Co­(OPiv) 2 (Piv = CO t Bu) as a catalyst . In this context, we have developed an Fe­(III) complex bearing a phenalenyl ligand that can successfully convert nitrile into primary amine via hydrosilylation in the presence of a less expensive silane PMHS.…”

“…60,61 successfully reduced nitriles to primary amines using tetramethyldisiloxane (TMDS) as the hydride source and Co(OPiv) 2 (Piv = CO t Bu) as a catalyst. 62 In this context, we have developed an Fe(III) complex bearing a phenalenyl ligand that can successfully convert nitrile into primary amine via hydrosilylation in the presence of a less expensive silane PMHS. To the best of our knowledge, to date, there have been no reports on nitrile reduction using the most economically and environmentally attractive combinations such as PMHS and an Fe-based catalyst.…”