RESUMEN
Hydrozirconation of the eta 2-phosphaalkyne complex [Pt(dppe)(eta 2-tBuCP)] with [ZrHCl(eta 5-C5H5)2], followed by treatment with the chlorophosphaalkene ClP=C(SiMe3)2 affords the eta 2-2,3-diphosphabutadiene complex [Pt(dppe)(eta 2-tBuC(H)=PP=C(SiMe3)2]. In the presence of [Pt(PPh3)2] the latter undergoes an addition reaction with water to afford the structurally characterised Pt(II) complex [Pt(dppe)(tBuCH2P(O)HPC(SiMe3)2].
RESUMEN
Reaction of 2,2'-difluoro-1,1'-biphenyl with chlorosulfonic acid and subsequent hydrolysis followed by neutralization with potassium or sodium hydroxide affords disodium or dipotassium 5,5'-disulfonato-2,2'-difluoro-1,1'-biphenyl (1a, 1b). On treatment of 1b with diphenyl- or phenylphosphine in the superbasic medium DMSO/KOH, phosphine ligand 2 or 3 with a disulfonated 1,1'-biphenyl backbone or a dibenzophosphole moiety is formed. The structure of the oxide of 5-phenyldibenzophosphole 3, which crystallizes as 4.2.5H(2)O in the monoclinic space group P2(1)/n with a = 13.799(3) A, b = 19.246(4) A, c = 17.764(4) A, beta = 105.63(3) degrees, and Z = 4, has been determined by X-ray analysis. Nucleophilic phosphination of 1a with NaPH(2) in liquid ammonia yields the sodium phosphide 5a which on protonation gives the water-soluble 5H-dibenzophosphole 5. Reaction of 1b with PH(3) in the superbasic medium DMSO/KOtBu affords 5b in addition to the oxidation product 6a. On oxidation of 5a or 5b with H(2)O(2), the sodium or potassium salts of the sulfonated phosphinic acids 6a or 6b, respectively, are formed. Alkylation of the sodium dibenzophospholide 5a with 2,2'-bis(chloromethyl)-1,1'-biphenyl or 1,4-di-O-p-toluenesulfonyl-2,3-O-isopropylidene-D-threitol yields the chiral water-soluble bidentate phosphine ligands 8 and 9, respectively.
RESUMEN
The first PH-functional phosphines (1, 3, and 5) containing the 1,1'-binaphthyl-2,2'-bis(methylene) or 1,1'-biphenyl-2,2'-bis(methylene) backbone have been obtained by two-phase phosphination of 2,2'-bis(halomethyl)-1,1'-binaphthyls with PH(3) or in a protected-group synthesis using P(SiMe(3))(3) as the starting material. The 4,5-dihydro-3H-dinaphtho[2,1-c:1',2'-e]phosphepine (1) is configurationally stable, as indicated by the inequivalence of the two CH(2) and naphthyl substituents in the (13)C{(1)H} NMR spectra. The X-ray crystal structure of 1.0.5C(6)H(5)CH(3) shows an intracyclic C-P-C angle of 99.5(2) degrees, the interplanar angle of the phosphepine ring system being 67.6(5) degrees. The borane adduct 7 of the secondary phosphine 1 has been employed for the syntheses of atropisomeric mono- and bidentate ligands (8-14) with the bulky 1,1'-binaphthyl moieties. Results of force field calculations on the conformations of 1, 3, and 14 are presented. The ability of these phosphines to form mononuclear and polynuclear complexes with transition-metal centers is discussed. Compound 14 exhibits a large variety of low-energy conformations, and some of them seem to be capable of forming mononuclear transition-metal complexes.
RESUMEN
Cationic phosphine ligands containing m-guanidinium phenyl substituents {Ph(3-n)P[C(6)H(4)-m-NHC(NH(2))(NMe(2))](n)}(n+) nCl(-) (n = 1-3) (17a-c) have been obtained by addition of dimethylcyanamide to the amino groups of tertiary (m-aminophenyl)phosphines in acidic medium. The tertiary (m-aminophenyl)phosphines Ph(3-n)P(C(6)H(4)-m-NH(2))(n) (4a-c) were prepared by reaction of (3-[N,N-bis(trimethylsilyl)amino]phenyl)magnesium chloride (1) with chlorophosphines Ph(3-n)PCl(n) followed by deprotection of the bis(trimethylsilyl)amino groups with methanol. Using a similar protected group synthesis as above, the secondary (m-aminophenyl)phosphine Ph(H)PC(6)H(4)-m-NH(2) (7) could be prepared as well. It may be employed as a building block for the syntheses of chiral bidentate phosphine ligands (11, 14, and 15) bearing m-aminophenyl substituents. The guanidinium phosphines 17b and 17c are readily soluble in water. A comparative study of 17b and 17c, the aryl alkyl guanidinium phosphines 18 and 19, and TPPTS (P(C(6)H(4)-m-SO(3)Na)(3)) in the aqueous phase palladium-catalyzed C-C coupling reaction between p-iodobenzoate and (trifluoroacetyl)propargylamine shows 17b to be of surmounting activity.
RESUMEN
Chiral water-soluble secondary phosphines (2-6) were obtained by nucleophilic phosphination of FC(6)H(4)-4-SO(3)K (1a), FC(6)H(3)-2,4-(SO(3)K)(2) (1b), and FC(6)H(4)-2-SO(3)K (1c) with RPH(2) (R = Ph, 2,4,6-Me(3)C(6)H(2), 2,4,6-iPr(3)C(6)H(2)) in the superbasic medium DMSO/KOH by employing steric control of substitution at phosphorus by bulky substituents R and sulfonic groups in the ortho position of the aromatic ring systems in 1b or 1c. The secondary phosphines may be deprotonated in DMSO/KOH to give phosphido anions which on reaction with alkyl halides (PhCH(2)Cl, Br(CH(2))(3)Br, and C(12)H(25)Br) yield mono- or bidentate tertiary phosphines (7-10). Ligands of this type are alternatively accessible by nucleophilic arylation of secondary phosphines, e.g. Ph(Me)PH or Ph(H)P(CH(2))(3)P(H)Ph with 1a or 1b, respectively. The crystal structure of the starting material 1b.H(2)O (space group P2(1)/m) has been determined. In the solid state of 1b.H(2)O the individual molecules are interconnected by ionic interactions between the potassium cations and the SO(3)(-) anions. The C-F bond (C(1)-F 1.347(4) Å) is shorter than that in C(6)H(5)F (1.356(4) Å). The unit cell of 7a.0.5H(2)O (space group P&onemacr;), the first structurally characterized chiral phosphine with a sulfonated phenyl substituent, contains the two enantiomers. Due to the asymmetrical substitution at phosphorus the PC(3) skeletons are significantly distorted (P(1)-C(1,11,31) 1.864(10), 1.825(8), 1.841(7) Å). The electronic structure of sulfonated fluorobenzenes FC(6)H(5)(-)(n)()(SO(3)M)(n)() (M = K, NH(4), n = 1-3) is discussed on the basis of quantum chemical calculations. In particular, the reactivity difference toward nucleophilic phosphination within the series is rationalized in terms of steric factors and of the -I effect of the sulfonic groups.