ChemInform Abstract: REDUCTION OF DIMETHYLFORMAMIDE WITH TRIALKYLSILANES AND DIALKYLCHLOROSILANES

Abstract

Dimethylformamid (I) wird in Tetrahydrofuran in Gegenwart von Katalysatoren durch Trialkyl‐ und Alkylchlorsilane (II) zu Trimethylamin (III) reduziert.

Metal-Catalyzed Reduction of HCONR′2, R′ = Me (DMF), Et (DEF), by Silanes to Produce R′2NMe and Disiloxanes: A Mechanism Unraveled

“…In 1985, the Voronkov group first reported that the reaction of various silanes R 2 R′SiH (R 2 R′ = Cl 2 Me, Cl 2 Et; Et 2 Me and Et 3 ) with DMF, in the presence of the metal complexes (NO) 2 PtCl 6 or [Me 2 NH 2 ] + [Rh(CO) 2 Cl 2 ] − , led to the formation of the corresponding disiloxanes. 1 More recently both Fe 2 (CO) 9 and Fe 3 (CO) 12 have been used as catalysts for the efficient reduction of N,N-dimethylbenzamide with the formation of benzyldimethylamine 2 and zinc acetate was shown to catalyze the reduction of aromatic heterocyclic amides. 3 In between these reports a number of groups have reported variations on the theme using different metal catalysts; "green" Pt resins; 4 Ru 3 (CO) 12 4a and related variants; 5 a range of other metal carbonyl complexes, 6 and the main group metal salt InBr 3 .…”

“…The initial hydrosilylation can proceed either via initial amide coordination to molybdenum as has been reported, 10 followed by η 2 -silane coordination after further loss of CO, or vice versa, initial coordination of the η 2 -SiH, followed by the amide. Molybdenum η 2 -silane σcomplexes, (CO) 5 Mo(η 2 -HSiR 3 ) have been detected by 1 H NMR spectroscopy in the photochemical reaction of group 6 metal carbonyls and the R 3 SiH. 14 Migration of R 3 Si group to oxygen can lead to the reductive elimination of the siloxymethyl amines R 3 SiOCH 2 NMe 2 , 4.…”

“…The transition metal-catalyzed reduction of amides by hydrosilanes is an efficient method for amine synthesis along with the appropriate disiloxane, − eq . 2 normalR 3 SiH + normalR ′ normalC ( O ) NR ″ 2 → Catalyst normalR 3 Si − normalO − SiR 3 + normalR ′ CH 2 NR ″ 2 …”

“…In 1985, the Voronkov group first reported that the reaction of various silanes R 2 R′SiH (R 2 R′ = Cl 2 Me, Cl 2 Et; Et 2 Me and Et 3 ) with DMF, in the presence of the metal complexes (NO) 2 PtCl 6 or [Me 2 NH 2 ] + [Rh(CO) 2 Cl 2 ] − , led to the formation of the corresponding disiloxanes . More recently both Fe 2 (CO) 9 and Fe 3 (CO) 12 have been used as catalysts for the efficient reduction of N , N -dimethylbenzamide with the formation of benzyldimethylamine and zinc acetate was shown to catalyze the reduction of aromatic heterocyclic amides .…”

Aminomethylation of Aminoferrocene, [(η5-C5H5)Fe(η5-C5H4NH2)], and (Anilino)chromiumtricarbonyl, [(η6-C6H5NH2)Cr(CO)3], by O-Triethylsilyl-hemiaminal, (Et3SiOCH2NMe2): The Role of Disparate Organometallic Electronic Effects in Modifying Product Outcomes

“…The first reports of this process by the groups of Calas (1962) and later Voronkov (1985) have remained largely unrecognized and uncited. In the early 2000’s, many groups studied this reaction to improve the chemoselectivity, functional group tolerance, catalyst composition and turn-overs, and reaction yields. − When catalyzed by Mo complexes, we demonstrated that this reduction proceeds via the initial hydrosilylation of the carbonyl group to produce ( O -silylhemiaminals), as illustrated in eq . These important intermediates can be isolated, purified, and stored indefinitely in an inert atmosphere. …”