Reaction prospecting by 31P NMR: enantioselective rhodium-DuPhos catalysed addition of ZnMe2 to diphenylphosphinoylimines

Reports of the use of first row transition metal complexes for the catalytic AH of imine are limited. In 2011 Beller and coworkers reported that a range of N-aryl substituted imines were hydrogenated to amines with ee ranging from 88 to 98% using Knölker's iron complex FeH(CO)2(Cp'OH) (5 mol%) in combination with the homochiral phosphoric acid (S)-TRIP (1 mol%) at 50 bar H2 and 65 °C. 23 In 2014 our group reported that an iron complex [FeBr(CO)2(L 1)]BF4 with the asymmetric ligand (S,S)-PPh2CHPhCHMeNHCH2CH2P i Pr2 (L 1) when activated with LiAlH4/iso-amylalcohol was active in the presence of 10 mol% KO t Bu for the AH of the N-diphenylphosphinoyl imine derived from 1-propiophenone to the amine (90% ee) at 20 atm H2 and 50 °C. 24 Bai et al have described the use of homochiral cyclopentadienone)iron complex for the AH of activated imines but the enantioselectivity was poor (ee of the amine up to 40%). 25 Otherwise there have been several reports of the ATH of activated imines by catalysts based on iron, 26-29 cobalt 30,31 and nickel. 32

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“…1 (S)-N-(1-(3-Chlorophenyl)ethyl)-P,P-diphenylphosphinamide (3f). 45 Off-white crystalline solid. Duplicate average of 37.0 mg (81% yield).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Enantioselective Hydrogenation of Activated Aryl Imines Catalyzed by an Iron(II) P-NH-P′ Complex

et al. 2019

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“…The aliphatic derivatives are not stable; as a rule, they are involved in the reaction without puri fication. The standard procedure for the removal of the Dpp fragment is acid solvolysis (a) on heating in concentrated HCl [60], (b) at ambient temperature in aqueous alcoholic solution of HCl [62,63], or (c) by treatment with gaseous HCl [61]. Yields vary from moderate to high.…”

Section: N Phosphinoyl Imines (Iii)mentioning

confidence: 99%

“…Yields vary from moderate to high. It is described that Dpp is removed under the action of BF 3 · Et 2 O [62] and upon the treatment of phosphinamide with trifluoroacetic anhy dride or the AcCl/DMAP system with simultaneous acylation of the resultant amine [63].…”

Section: N Phosphinoyl Imines (Iii)mentioning

confidence: 99%

Stable synthetic equivalents of N-unsubstituted imines: Part 1. Synthesis

et al. 2012

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“…However, the reaction of N-phosphinylimines with dialkylzincs is very slow and low yields of the addition products are obtained in long reaction times unless an additive is used to facilitate the reaction. [6][7][8][9][10][11][12] β-Aminoalcohols are among the most efficient promoters for these addition reactions. A variety of them have shown to induce excellent enantioselectivities, but, in most cases, the use of a stoichiometric amount of the aminoalcohol ligand was necessary.…”

Section: Introductionmentioning

confidence: 99%

Polymer-supported l-prolinol-based catalysts for the enantioselective addition of dialkylzinc reagents to N-(diphenylphosphinyl)imines

Almansa

Collados

Guijarro

et al. 2013

Tetrahedron: Asymmetry

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L-Prolinol-based ligands anchored to Merrifield or Wang-type resins have shown to form efficient catalysts for the enantioselective addition of dialkylzinc reagents to N-(diphenylphosphinyl)imines. The enantioselectivity achieved with the polymeric catalyst (ee up to 88%) is slightly lower than the one obtained with the homogeneous ligand N-benzyl-L-prolinol, but the polymersupported ligand presents the advantage of its recyclability: it can be recovered and used in up to six consecutive catalytic cycles with only a slight detriment in the enantiomeric excess. The phosphinamides obtained as addition products can be transformed into the corresponding optically enriched α-branched primary amines under mild acidic conditions.

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Reaction prospecting by 31P NMR: enantioselective rhodium-DuPhos catalysed addition of ZnMe2 to diphenylphosphinoylimines

Cited by 17 publications

References 18 publications

Enantioselective Hydrogenation of Activated Aryl Imines Catalyzed by an Iron(II) P-NH-P′ Complex

Enantioselective Hydrogenation of Activated Aryl Imines Catalyzed by an Iron(II) P-NH-P′ Complex

Stable synthetic equivalents of N-unsubstituted imines: Part 1. Synthesis

Polymer-supported l-prolinol-based catalysts for the enantioselective addition of dialkylzinc reagents to N-(diphenylphosphinyl)imines

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