- Primary Amination of Ar2P(O)-H with (NH4)2CO3as an Ammonia Source under Simple and Mild Conditions and Its Extension to the Construction of Various P-N or P-O Bonds
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A facile and efficient method for the synthesis of primary phosphinamides from Ar2P(O)-H reagents with stable and readily available ammonium carbonate as an ammonia source is disclosed herein for the first time. This ethyl bromoacetate-mediated primary am
- Han, Ya-Ping,Tan, Yushi,Yang, Shang-Dong,Zhang, Hong-Yu,Zhang, Yuecheng,Zhao, Jiquan
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- Enantioselective Hydrogenation of Activated Aryl Imines Catalyzed by an Iron(II) P-NH-P′ Complex
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Chiral amines are key building blocks in synthetic chemistry with numerous applications in the agricultural and pharmaceutical industries. Asymmetric imine hydrogenation, particularly with iridium catalysts, is well developed. However, imine reduction still remains challenging in the context of replacing such a precious metal with a cheap, nontoxic, and environmentally friendly substitute such as iron. Here, we report that an unsymmetrical iron P-NH-P′ catalyst that was previously shown to be effective for the asymmetric hydrogenation of aryl ketones is also a very effective catalyst for the asymmetric hydrogenation of prochiral aryl imines activated with N-diphenylphosphinoyl or N-tosyl groups. The P-NH-P′ abbreviation stands for (S,S)-PPh2CHPhCHPhNHCH2CH2PiPr2. Density functional theory results suggest that, surprisingly, the NH group on the catalyst activates and orients the imine to hydride attack by hydrogen bonding to the PO or SO group on the imine nitrogen, as opposed to the imine nitrogen itself. This may explain why N-Ph and N-Bu imines are not hydrogenated.
- Seo, Chris S. G.,Tannoux, Thibault,Smith, Samantha A. M.,Lough, Alan J.,Morris, Robert H.
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p. 12040 - 12049
(2019/10/02)
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- A practical method for N-alkylation of phosphinic (thio)amides with alcohols via transfer hydrogenation
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This manuscript describes a modular method for preparing N-alkyl phosphinic amides from primary or secondary alcohols and primary phosphinic amide (R1R2P = ONH2) nucleophiles via transfer hydrogenation. The transformation typically proceeds in excellent yields, employs conveniently available reagents, and produces water as the only byproduct.
- Jankins, Tanner C.,Qin, Zi-Yang,Engle, Keary M.
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p. 3272 - 3281
(2019/05/15)
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- Cobalt-catalyzed oxidative arylmethylation of phosphorylamides
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A cobalt-catalyzed strategy for N-arylmethylation of phosphorylamides was herein achieved with the assistance of azodiisobutyronitrile as the radical initiator and di-tert-butyl peroxide as the oxidant. Both methylarenes and diaryl methanes were compatible under the oxidative conditions, expressing broad substrate scope (51 examples) and high efficiency (up to 87% yield).
- Xiao, Jing,Li, Ping,Zhang, Yingjun,Xie, Dexun,Peng, Zhihong,An, Delie,Dong, Wanrong
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p. 4558 - 4568
(2018/07/30)
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- Copper-Catalyzed Enantioselective Alkylation of Enolizable Ketimines with Organomagnesium Reagents
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Inexpensive and readily available organomagnesium reagents were used for the catalytic enantioselective alkylation of enolizable N-sulfonyl ketimines. The low reactivity and competing enolization of the ketimines was overcome by the use of a copper–phosphine chiral catalyst, which also rendered the transformation highly chemoselective and enantioselective for a broad range of ketimine substrates.
- Ortiz, Pablo,Collados, Juan F.,Jumde, Ravindra P.,Otten, Edwin,Harutyunyan, Syuzanna R.
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p. 3041 - 3044
(2017/03/14)
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- Enantioselective Hydrosilylation of Imines Catalyzed by Chiral Zinc Acetate Complexes
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A series of zinc acetate complexes with optically pure diphenylethanediamine (DPEDA)-derived ligands have been employed as enantioselective catalyst for the hydrosilylation of various imines. High control of stereoselectivity (up to 97% ee) and excellent yields (up to 96%) were gained for a broad range of N-phosphinoylimines by using (R,R)-N,N′-dibenzyl-1,2-diphenylethane-1,2-diamine. This is the first successful application of an air-stable and environmentally friendly chiral Zn(OAc)2 complex instead of the previously used harmful diethylzinc in the asymmetric reduction of the C=N double bond.
- Bez?ada, Agata,Szewczyk, Marcin,Mlynarski, Jacek
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p. 336 - 342
(2016/01/15)
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- Highly enantioselective transfer hydrogenation of ketones with chiral (NH)2P2 Macrocyclic Iron(II) complexes
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Bis(isonitrile) iron(II) complexes bearing a C2-symmetric diamino (NH)2P2 macrocyclic ligand efficiently catalyze the hydrogenation of polar bonds of a broad scope of substrates (ketones, enones, and imines) in high yield (up to 99.5 %), excellent enantioselectivity (up to 99 % ee), and with low catalyst loading (generally 0.1 mol %). The catalyst can be easily tuned by modifying the substituents of the isonitrile ligand. Paying the iron price: Bis(isonitrile) iron(II) complexes with a C2-symmetric diamino (NH)2P2 macrocyclic ligand efficiently catalyze the hydrogenation of polar bonds of a broad scope of substrates (ketones, enones, imines) in high yield (up to 99.5 %), excellent enantioselectivity (up to 99 % ee), and with low catalyst loading (generally 0.1 mol %).
- Bigler, Raphael,Huber, Raffael,Mezzetti, Antonio
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supporting information
p. 5171 - 5174
(2015/04/27)
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- Highly enantioselective Pd-catalyzed asymmetric hydrogenation of activated imines
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(Chemical Equation Presented) Pd/bisphosphines complexes are highly effective catalysts for asymmetric hydrogenation of activated imines in trifluoroethanol. The asymmetric hydrogenation of N-diphenylphosphinyl ketimines 3 with Pd(CF3CO2)/(S)-SegPhos indicated 87-99% ee, and N-tosylimines 5 could gave 88-97% ee with Pd-(CF3CO 2)/(S)-SynPhos as a catalyst. Cyclic N-sulfonylimines 7 and 11 were hydrogenated to afford the useful chiral sultam derivatives in 79-93% ee, which are important organic synthetic intermediates and structural units of agricultural and pharmaceutical agents.
- Wang, You-Qing,Lu, Sheng-Mei,Zhou, Yong-Gui
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p. 3729 - 3734
(2008/02/04)
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- Nickel-catalysed addition of dialkylzinc reagents to N-phosphinoyl- and N-sulfonylimines
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A catalytic amount of a nickel complex (0.1-5.3 mol %) extraordinarily increases the reaction rate of the addition of dialkylzinc reagents to N-(diphenylphosphinoyl)- or N-(benzenesulfonyl)imines. The reaction of imines derived from both aromatic and alip
- Almansa, Raquel,Guijarro, David,Yus, Miguel
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p. 1167 - 1174
(2007/10/03)
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- Enantioselective MSPV reduction of ketimines using 2-propanol and (BINOL)AlIII
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A highly enantioselective Meerwein-Schmidt-Ponndorf-Verley (MSPV) reduction of N-phosphinoyl ketimines by (BINOL)AlIII/2-propanol is reported. Yields ranging between 79 and 85% with high enantiomeric excesses (93-98%) are observed for a wide ra
- Graves, Christopher R.,Scheidt, Karl A.,Nguyen, SonBinh T.
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p. 1229 - 1232
(2007/10/03)
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- Unprecedented asymmetric induction through configurationally stable lithium N-(α-methylbenzyl)phosphinamides. A new entry to enantiomerically pure γ-aminophosphinic acids and esters
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The first examples of configurationally stable N-benzyl-N-phosphinoyl carbanions are described. Their applications to the synthesis of homochiral γ-aminophosphinic acids and esters via highly enantioselective dearomatising reactions are shown. The Royal S
- Fernandez, Ignacio,Ruiz Gomez, Gloria,Alfonso, Ignacio,Iglesias, Maria J.,Lopez Ortiz, Fernando
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p. 5408 - 5410
(2007/10/03)
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- CATALYTIC HYDROGENERATION OF CARBON-HETEROATOM DOUBLE BONDS
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Process for catalytically hydrogenating carbon-heteroatom double bonds, in particular for asymmetrically catalytically hydrogenating simple ketones, which includes the step of reacting the substrate with hydrogen in the presence of a hydrogenation catalyst and of a base, characterized in that the hydrogenation catalyst is a 5-coordinate ruthenium complex which in each case has a monophosphine ligand and a bidentate P-N ligand.
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- Transfer hydrogenation process
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A catalytic transfer hydrogenation process is provided. The process can be employed to transfer hydrogenate N-substituted imines and iminium salts, which are preferably prochiral. The catalyst employed in the process is preferably a metal complex with one hydrocarbyl or cyclopentadienyl ligand and which is also coordinated to defined bidentate ligands. Preferred metals include rhodium, ruthenium and iridium. Preferred bidentate ligands are diamines and aminoalcohols, particularly those comprising chiral centres. The hydrogen donor is advantageously a mixture of triethylamine and formic acid. A process for the production of primary and secondary amines using the catalytic transfer hydrogenation of the N-substituted imines and iminium salts is also provided.
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Page column 24
(2008/06/13)
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- Enantioselective addition of methyllithium to 2-furaldehyde imine with the aid of chiral ligand
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The chiral ligand mediated enantioselective reaction of methyllithium with furylimines was investigated in the presumed 1,4- and 1,2-addition manners. The imines bearing a phosphinoyl or sulfonyl group on the imine nitrogen atom gave rather poor enantiose
- Taniyama, Daisuke,Kanai, Motomu,Iida, Akira,Tomioka, Kiyoshi
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p. 165 - 168
(2007/10/03)
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- Organic phosphorus compounds 106.1 a 31P-NMR study of phosphinous-, phosphinic-, and thiophosphinic amides
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The synthesis, physical, chemical and spectroscopic properties of eight different types of phosphinous-, phosphinic-and thiophosphinic amides are reported. It is shown that the 31P-chem. shifts of tertiary amides are at lower magnetic field than that of secondary amides. As an exception, in the bis(tertiary butyl) series this trend is reversed.
- Maier, Ludwig,Diel, Peter J.
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p. 273 - 300
(2007/10/03)
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