A new synthetic route to aminophosphines

BINAP aminophosphines are prevalent N,P-bidentate, chiral ligands for asym. catalysis. While modification via the BINAP-nitrogen linkage is well explored and has provided a diverse body of derivs., modification of the other substituents of the phosphorous center is another avenue in generating new congeners of this important class of chiral ligands. Herein reported are new BINAP aryl aminophosphines with electron rich or deficient substituents on the aryl rings. This scalable synthesis converted readily available starting material, (S)-BINOL, to a key intermediate (S)-NOBIN, from which the final chiral aminophosphines were prepd. via a palladium-catalyzed, phosphonylation reaction. The aryl substituents are able to modify the electronic properties of the phosphorous center as indicated by the range of 31P-NMR shifts of these new ligands. A computational anal. was performed to linearly quantitate contributions to the 31P-NMR shifts from both resonance and field effects of the substituents. This correlation may be useful for designing and prepg. other related aminophosphines with varying ligand properties.

Angewandte Chemie International Edition, 2010

Journal of Organometallic Chemistry, 2008

Two new aminophosphines, benzyl-N(Ph 2 P) 2 and 2-picolyl-N(Ph 2 P) 2 , have been synthesized. Oxidation of the aminophosphines with either hydrogen peroxide, elemental sulfur and selenium gave the corresponding oxides, sulfides and selenides benzyl-N(Ph 2 P@E) 2 and 2-picolyl-N(Ph 2 P@E) 2 , where E = O, S, or Se. Complexes [benzyl-N(Ph 2 P) 2 ]MCl 2 and [2-picolyl-N(Ph 2 P) 2 ]MCl 2 , where M = Pd, Pt, were obtained by the reaction of the aminophosphines with MCl 2 (cod). The new compounds were characterised by NMR, IR spectroscopy and microanalysis. Furthermore, representative solid-state structures of the palladium and platinum complexes were determined using single crystal X-ray diffraction analysis. The palladium complexes were further investigated as potential catalysts in C-C coupling reactions.

Topics in current chemistry (Journal), 2017

This review summarizes significant contributions reported on aminophosphine oxides (AmPOs), specifically those containing at least one amino group present as amino substituents on α- and β-carbons including direct P-N bond containing molecules. AmPOs have additional 'N' site(s), including highly basic 'P=O' groups, and these features make favor smooth and unexpected behavior. The most striking manifestations of flexibility of AmPOs are that they are exciting ligand systems for the coordination chemistry of actinides, and their involvement in catalytic organic reactions including enantioselective opening of meso-epoxides, addition of silyl enol ethers, allylation with allyltributylstannane, etc. The diverse properties of the AmPOs and their metal complexes demonstrate both the scope and complexity of these systems, depending on the basicity of phosphoryl group, and nature of the substituents on the pentavalent tetracoordinate phosphorus atom and metal. Two components ...

Russian Chemical Bulletin

A condensation of bis(hydroxymethyl)arylphosphines with 3- and 4-aminobenzonitriles leads to the corresponding 3,7-diaryl-1,5-bis(cyanophenyl)-1,5-diaza-3,7-diphosphacyclooctanes. Acyclic (aryl)bis[N-(2-cyanophenyl)aminomethyl]phosphines are formed in the case of 2-aminobenzonitrile. Molecular and crystalline structure of the compounds obtained was studied by X-ray diffraction analysis.

Polyhedron, 2006

The synthesis, derivatization and coordination behavior of N-diphenylphosphinomorpholine (1) and N-diphenylphosphinopiperazine (2) is described. Ligands 1 and 2 react with elemental sulfur or selenium to give the corresponding chalcogenides in good yield. Reaction of 1 with paraformaldehyde leads to the insertion of methylene into P-N bond to give phosphine oxide, Ph 2 P(O)CH 2 NC 4 H 8 O in quantitative yield. Treatment of 2 with [Pd(COD)Cl 2 ] produces both the mononuclear [PdCl 2 {(Ph 2 PNC 4 H 8 O)-jP} 2 ] and the chloro-bridged dinuclear complex, [(OC 4 H 8 NPh 2 P)Pd-(l-Cl)Cl] 2 whereas the similar reaction of 2 with [Pt(COD)Cl 2 ] affords only the mononuclear complex [PtCl 2 {(Ph 2 PNC 4 H 8 O)-jP} 2 ]. Interestingly, ligand 2 reacts with Mo(0), W(0), Ru(II), Pd(II), Pt(II) and Au(I) derivatives to furnish exclusively mononuclear complexes. The molecular structures of Ru(II) and Pd(II) dimer have been confirmed by X-ray studies.

Polyhedron, 2005

The reaction of aminophosphines and aminobis(phosphines) with aldehydes leads to either insertion of carbon fragments into the P(III)-N bonds or formation of a-hydroxyphosphine oxides through P(III)-N bond cleavage. Reaction of 1,2-C 6 H 4 {N(H)PPh 2 } 2 with paraformaldehyde gives the P(III)-N bond inserted product 1,2-C 6 H 4 {N(H)CH 2 P(O)Ph 2 } 2 , whereas 1,3-C 6 H 4 {N(H)PPh 2 } 2 forms an analogous product but with an additional methylene group inserted between the two nitrogen centers through nucleophilic addition to form a bicyclic derivative, 1,3-C 6 H 4 {Ph 2 P(O)CH 2 N(l-CH 2)NCH 2 P(O)Ph 2 }. Reactions of Ph 2 PN(H)Ph with aromatic aldehydes, RCHO (R = C 6 H 4 OH-o, 5-BrC 6 H 3 OH-o, (g 5-C 5 H 5)Fe(g 5-C 5 H 4-)) lead to the insertion of ÔRCHÕ into the P(III)-N bond to give Ph 2 P(O)CH(R)N(H)Ph. The reactions of aminobis(phosphine), Ph 2 PN(n Bu)PPh 2 with both aromatic and aliphatic aldehydes lead to the formation of a-hydroxy phosphine oxide derivatives of the type Ph 2 P(O)CH(R)OH, through P(III)-N bond cleavage. The N-bridged bis(phosphine oxide) n PrN(CH 2 P(O)Ph 2) 2 readily forms chelate complexes with U(VI), Th(IV) and Gd(III) derivatives.

Inorganic Chemistry, 2002

Variants of the -aminophosphine L 1 [Ph2PCH2CH(Ph)NHPh] containing additional nitrogen donor functions have been prepared. These functions are branched off the C atom adjacent to the P atom, or the P atom itself. Ligand [Ph2PCH(-o-C6H4NMe2)CH(Ph)NHPh] has been obtained as a mixture of two diastereomers L 3A and L 3B by lithiation of L 2 [Ph2PCH2(-o-C6H4NMe2)] with n-BuLi followed by PhCH=NPh addition and hydrolysis. The diastereomers have been separated by fractional crystallization from ethanol. Ligand Et2NCH2P(Ph)CH2CH(Ph)NHPh has been obtained as a mixture of two diastereomers L 5A and L 5B starting with P-Ph reductive cleavage of L 1 by lithium and subsequent hydrolysis to give PhP(H)CH2CH(Ph)NHPh (mixture of two diastereomers L 4A and L 4B). The latter reacts with diethylamine and formaldehyde to afford the L 5 diastereomeric mixture. Complexes RhCl(CO)(L) (L = L 3A , 1 A ; L 3B , 1 B ; L 5A/B , 2 A/B) were obtained by reaction of [RhCl(CO)2]2 and the appropriate ligand or ligand mixture. Complexes 1 A , 1 B , and 2 A have been isolated in pure form and characterized by classical techniques and by single crystal X-ray diffraction. All structures exhibit a bidentate -P,-N(NHPh) mode similar to the complex containing L 1. While complexes 1 A or 1 B are stable in CDCl3 solution, complex 2 A slowly converts to its diastereomer 2 B. This unexpected epimerization appears to take place by inversion at the Rh-coordinated P center, an apparently unprecedented phenomenon. A mechanism based on a reversible P-C bond oxidative addition is proposed. The influence of the pendant nitrogen function of the diaminophosphines L 3A and L 5A/B on the rhodium catalytic activity in styrene hydroformylation has been examined and compared to that of the aminophosphines L 1 or L 2. The observed trends are related to the basicity of the dangling amine function and to its proximity to the metal center.

Inorganic Chemistry

All manipulations were carried out under purified N 2 using standard Schlenk and/or Glove-box techniques. Deuterated solvents were obtained from Sigma-Aldrich and Cambridge Isotopes Laboratories and were dried prior to use. All solvents were dried by distillation from appropriate drying agents and were S3 stored over 3 Å molecular sieves under an N 2 atmosphere prior to use. Paraformaldehyde, dimethylamine (2.0 M in MeOH), n-butyllithium (1.6 M in hexanes), 2-bromopyridine, 2-methylpyridine, and Me NCH CH 2 Cl•HCl were purchased from Sigma Aldrich and used without purification. LiAlH 4 was purchased from Sigma Aldrich and recrystallized from Et 2 O prior to use. Ph 2 PCl, i Pr 2 PCl, t Bu 2 PCl were purchased from Alfa Aesar or Strem Chemicals. K 2 PtCl 4 was purchased from Pressure Chemicals. Syntheses of [Pt 2 Me 4 (-SMe 2) 2 ], (cod)PtMe 2 , and (cod)PtCl 2 were performed according to literature procedures. 1 Modified procedures (Sections S.1.2 and S.1.3) were used to prepare known species L 1 , L 8 , 2, and 12. 2 1 H and 31 P NMR data obtained for these species is provided for comparison with other complexes in this study. Elemental analyses were performed by Analytical Services in the Department of Chemistry, The University of British Columbia. ESI-MS and EI-MS were recorded on Waters LCMS and Kratos MS-50 instruments, respectively. The observed isotope patterns were in agreement with calculated patterns in all cases, and the highest intensity signal is reported. The phosphine ligands prepared in this study were readily oxidized by air, and we were unable to obtain satisfactory elemental analyses for those ligands which exist as liquids at room temperature. NMR spectra were recorded on 300 or 400 MHz Bruker Avance NMR spectrometers. NMR experiments were performed at 23 °C and chemical shifts () are reported in ppm. The multiplicity of signals with 195 Pt satellites are reported as the multiplicity of the parent signal, with the presence of satellites is indicated by a reported J PtH , J PtC , or J PtP coupling constant. The term 'Pt-shoulders' refers to signals exhibiting coupling to 195 Pt where the satellites are not resolved from the parent signal. The following abbreviations are used: s = singlet, d = doublet, t = triplet, sept = septet, m = multiplet, ov = overlapping AB (subscript) indicates a second order AB spin system, v = virtual. S.1.2 Ligand Syntheses: S4 General Procedure for Preparation of Diorganophosphine Reagents Ad 2 PH was prepared from adamantane and PCl 3 as reported previously. 3 While commercially available, we found that Ph 2 PH, i Pr 2 PH, and t Bu PH were more economically prepared by treatment of an appropriate diorganophosphine chloride (R 2 PCl) with LiAlH 4. Caution: treatment of neat i Pr 2 PCl and Ph 2 PCl with LiAlH 4 is exothermic and must be done slowly to avoid vaporization of the phosphine. Example procedure: A Schlenk flask was charged with i Pr 2 PCl (5.0 g, 0.032 mol) and a stir bar under an atmosphere of N 2 and cooled to 0 °C. Solid LiAlH 4 (0.80 g, 0.021 mol) was added in ~50 mg portions over a period of an hour. The reaction was allowed to warm to room temperature after the addition was complete, and was stirred for 16 hours. Vacuum distillation of the product provided 1.58 g (41%) of i Pr 2 PH. Synthesis of L 1 (Ph 2 PCH 2 NMe 2) A reaction vessel fitted with a Teflon screw-cap and equipped with a stir bar was charged with Ph 2 PH (2.36 g, 0.013 mol) and paraformaldehyde (0.38 g, 0.013 mol 'H 2 CO'). A solution of HNMe 2 (0.013 mol, 2.0 M in MeOH) was added by syringe with stirring. The reaction vessel was heated to 60 °C for 9 h. The product was collected by distillation (bp. 348 °C), providing L 1 as a colourless oil. Yield 2.94 g (89%). The NMR data is similar to that previously reported in the literature.

Inorganic Chemistry, 2003

The Staudinger reaction of N(CH 2 CH 2 NR) 3 P [R ) Me (1), i Pr ] with 1 equiv of N 3 SO 2 C 6 H 4 Me-4 gave the ionic phosphazides [N(CH 2 CH 2 NR) 3 PN 3 ][SO 2 C 6 H 4 Me-4] [R ) Me (3), R ) i Pr (5a)], and the same reaction of 2 with N 3 SO 2 C 6 H 2 Me 3 -2,4,6 gave the corresponding aryl sulfinite 5b. On the other hand, the reaction of 1 with 0.5 equiv of N 3 SO 2 Ar (Ar ) C 6 H 4 Me-4) furnished the novel ionic phosphazide {[N(CH 2 CH 2 NMe) 3 P] 2 (µ-N 3 )}[SO 2 Ar] (6). Data that shed light on the mechanistic pathway leading to 3 were obtained by low temperature 31 P NMR spectroscopy.