Dmitry V. Moiseev

Characterization of Secondary and Primary (Hydroxymethyl)Phosphines and Their Oxidation Products: Synergism in Pulp-Bleaching

Abstract With the aim of learning about the synergistic effect of a combination of (HOCH2)3P and Na2S2O4 for the bleaching of mechanical pulps, reactions of (HOCH2)3P (and its associated precursor, (HOCH2)4P+Cl−) with Na2S2O4 were studied in aqueous media under Ar and in air. The secondary phosphine (HOCH2)2PH is the major product in a 1:1 reaction of (HOCH2)3P and Na2S2O4 under Ar, the formaldehyde being removed in the form of HOCH2SO3Na and HOCH2SO2Na; the latter is Rongalite, itself an industrial bleaching agent. Significant amounts of the primary phosphine HOCH2PH2 are also seen. When the reaction is performed in air, the oxide (HOCH2)2P(O)H is the main product. Reaction of (HOCH2)4P+Cl− with Na2S2O4 (even under Ar) leads to solely the oxidation products: (HOCH2)3PO, (HOCH2)3PS, and (HOCH2)2P(O)OH. 31P{1H} and 1H NMR spectral data for secondary and primary (hydroxymethyl)phosphines and their oxidation products are reported for the first time. The toxicity of the primary and secondary phosphines is likely to curtail their use in commercial bleaching processes. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT

Reversible decomposition of mono(α-hydroxy)-phosphines and their reaction with α,β-unsaturated aldehydes

The mono(α-hydroxy)phosphines R2PCH(OH)R′ (R = Ph, R′ = H, Et, CH2Ph, Ph, p-X-C6H4; R = cyclohexyl, R′ = Ph) are prepared under solvent-free conditions by a 1:1 reaction of Ph2PH with the appropria...

Reactions of a Phosphinoaldehyde with PdII, RhI, and IrI Precursors, Including the Formation of Complexes Containing a P,OH-Chelated Phosphinohemiacetal Ligand: a New Bonding Mode

The complexes trans-PdCl(2)[eta(1)-P-(Ph(2)P)CH(Ph)CH(Me)CH(OMe)(2)](2) (1) and M(H)Cl[eta(2)-P,OH-(Ph(2)P)CH(Ph)CH(Me)CH(OH)OMe][eta(2)-P,C(O)-(Ph(2)P)CH(Ph)CH(Me)C(O)], M = Rh (3) and Ir (4), are synthesized by reacting the phosphinoaldehyde [3-(diphenylphosphino)-3-phenyl-2-methyl]propionaldehyde [(Ph(2)P)(2)CH(Ph)CH(Me)CHO] with trans-PdCl(2)(PhCN)(2), [RhCl(COD)](2), and [IrCl(COD)](2), respectively, in MeOH; trans-PdCl(2)[eta(1)-P-(Ph(2)P)CH(Ph)CH(Me)CHO](2) (2) is isolated from the same reaction in CH(2)Cl(2). One diastereomer of each of the complexes 1, 3 x MeOH, and 4 x MeOH was characterized by X-ray analysis. The stereochemistry of such complexes in the solid state and in solution (MeOH and CH(2)Cl(2)) is discussed. In CD(2)Cl(2), NMR data suggest that the coordinated hemiacetal moiety of 3 (but not 4) undergoes reversible loss of MeOH; this process is associated with equilibria between various diastereomers of 3 that were investigated by (31)P{(1)H}, (13)C{(1)H}, (1)H, (1)H{(31)P}, and HSQC and HMBC (1)H/(31)P{(1)H} and (1)H/(13)C{(1)H} NMR spectroscopies. Complexes 3 and 4 reveal a new chelate bonding mode via a P atom and the hydroxyl O atom of a hemiacetal. Solvent-dependent stereochemical changes within solution species imply that such chiral phosphinoaldehydes are not likely to be useful ligands for applications in asymmetric catalysis, although conditions are suggested for testing the complexes as potential precursors for nonasymmetric catalytic processes.

Lignin-type, α,β-unsaturated aldehydes of lignin-type in organic solvents

A 1:1 reaction of [HO(CH2)3]3P with 4-hydroxy-3-methoxy-cinnamaldehyde (coniferaldehyde) or 3,5-dimethoxy-4-hydroxycinnamaldehyde (sinapaldehyde) in acetone at room temperature affords phosphonium zwitterions of the type R3P+CH(4-O−-Ar)CH2CHO; other phosphines [R = Et, n-Bu, (CH2)2CN, and p-Tol] do not react under the same conditions. In alcohols R’OH(D) [R’ = CD3, Et, (CD3)2CD, s-Bu, HOCH2CH2], the above phosphines (except the cyano-derivative) and those where R = i-Pr, Cy, Me2Ph, MePh2 do react within an equilibrium established between the reactants and the zwitterion-hemiacetal products R3P+CH(4-O−-Ar)CH2CH(OH)(OR′) that are formed as a mixture of two diastereomers. The nature of the phosphine and the alcohol affects the equilibrium and the diastereomeric ratio.

Interaction of Tris(3-Hydroxymethyl)Phosphine with Cinnamic Acids

Abstract Phosphonium zwitterions of the known type R3P+CH(Ar)CH2CO2 − (II) are obtained as a racemic mixture in moderate yield via a 1:1 reaction of cinnamic acids (Ar = phenyl, or substituted phenyl) with [HO(CH2)3]3P in acetone at room temperature under Ar. The products are characterized by elemental analysis, 31P{1H}-, 1H-, and 13C{1H}-NMR spectroscopies, and mass spectrometry, although they contain a minor coproduct formed via neutralization of the positive and negative charges of II with the respective acid and phosphine reactants (see Experimental Section). In CD3OD, the monodeuterated salts R3P+CH(Ar)CH(D)CO2 − are formed as a mixture of diastereomers with d.r. values of ∼2 to 8, depending on substituent groups present in the organic acid; in these studies, 2-HO-cinnamic acid is the most reactive, and β-methylcinnamic acid is the least reactive. GRAPHICAL ABSTRACT

Reaction of [HO(CH2)3]3P with α,β-Unsaturated Ketones Containing a Phenylpropanoid Backbone

Abstract Interaction of 3,4-(MeO)2-benzylideneacetone with [HO(CH2)3]3P (THPP) was studied in CD3OD by NMR to compare reactivity of a phenylpropanoid α,β-unsaturated ketone with a corresponding α,β-unsaturated aldehyde. In the presence of HCl, both the ketone and a related cinnamaldehyde first establish an equilibrium with the product formed by nucleophilic attack of the THPP at the C˭O bond, [ArCH˭CHCX(OD)PR3]+Cl−(X˭H or CH3, Ar˭Ph or 3,4-(MeO)2C6H3). The ketone salt then slowly transforms into [R3PCH(Ar)CH(D)C(O)CD3]+Cl−, the phosphonium product of nucleophilic attack of THPP at the C˭C bond, whereas the final product from the aldehyde is the (α-ether)phosphonium chloride [ArCH˭CHCH(OCD3)PR3]+Cl−. In aqueous media, in the absence of HCl, 4-HO-benzylideneacetone, which is similar to a lignin-type, α,β-unsaturated aldehyde model compound, interacts with THPP to afford a stable phosphonium zwitterion, in contrast to the previously studied aldehyde model, which forms dimeric, bisphosphonium products. GRAPHICAL ABSTRACT

Interaction of PH3 with Acetaldehyde in Aqueous Media and Chemistry of (HO(Me)CH) 4PCl

The known phosphonium chloride [HO(Me)CH]4PCl was prepared at ambient conditions from PH3 and acetaldehyde in aqueous HCl, and characterized by elemental analysis and 1H and 31{1H} NMR spectroscopy. Attempts to obtain the tertiary phosphine [HO(Me)CH]3P via reaction of [HO(Me)CH]4PCl with Na2SO3 or Et3N in aqueous media under Ar revealed that [HO(Me)CH]3P is unstable and equilibrates with the secondary phosphine [HO(Me)CH]2PH and acetaldehyde. A 1:4 reaction of [HO(Me)CH]4PCl with NaHSO3 at room temperature under Ar affords first the oxide [HO(Me)CH]2P(O)H and then the phosphinic acid [HO(Me)CH]2P(O)OH. A 1:1 reaction of [HO(Me)CH]4PCl with Na2S2O3 affords the sulfide [HO(Me)CH]3PS. 31{1H} and 1H NMR data for all the (α-hydroxyethyl)phosphorus species are reported for the first time.

Competing reactions of hydrophenylation and phenylation in tetraphenylantimony chloride methyl acrylate palladium chloride system

A new catalytic reaction of the competing phenylation and hydrophenylation in air of methyl acrylate with tetraphenylantimony chloride in the presence of PdCl2 (0.04 mol per 1 mol of organometallic compound) in acetonitrile at 50°C for 6 h was studied. The yields of methyl cynnamate and methyl hydrocynnamate were 0.73 and 0.27 mol mol−1 respectively. The products ratio obtained depends slightly on the process duration, the Ph4SbCl and methyl acrylate ratio, and the structure of Pd salt [PdCl2, Pd(OAc)2, Li2PdCl4], but significantly on the nature of a solvent (MeCN > DMF > THF). The use of Ph4SbCl instead of Ph4SbBr leads to decrease in the yield of methyl hydrocynnamate to 0.04 mol mol−1. In the reactions of Ph4SbX (X = F, I, OAc, O2CEt) the product is not formed at all.

Phenyl Derivatives of Antimony(III, V) and Bismuth(III, V) in the Presence of Palladium Salts, as C-Phenylating Agents for Methyl Acrylate

The C-phenylation of methyl acrylate to methyl cynnamate with Ph3Sb, Ph3SbX2 (X = Cl, OAc), Ph3Bi, and Ph3BiX2 (X = OAc, O2CEt) in the presence of PdCl2, Pd(OAc)2, Li2PdCl4, NaPd(OAc)Cl2, and Na2Pd(OAc)2Cl2 was studied to show that the reactions with Ph3Sb and Ph3Sb(OAc)2 are more selective and give higher yields of the target product than those with Ph3Bi and Ph3Bi(OAc)2, while Ph3M(OAc)2 are preferred over Ph3M. Copper(II) alkanecarboxylate additives have no effect on the yield of methyl cynnamate in the reactions with Ph3Sb.

New water-soluble (hydroxymethyl)triphosphine [(HOCH2)2PCH2CH2]2PCH2OH, a derived PdII(triphosphine) complex, and triphosphine trioxide

An aqueous solution of (hydroxymethyl)triphosphine [(HOCH2)2P(CH2)2]2PCH2OH (II) was synthesized in situ by treatment of the triphosphine H2P(CH2)2PH(CH2)2PH2 with formaldehyde. Addition of a CH2Cl2 solution of trans-PdCl2(PhCN)2 to an in situ aqueous solution of II resulted in the formation of a species thought to be [PdCl{[(HOCH2)2P(CH2)2]2PCH2OH}]+Cl−. Attempts to isolate the complex were unsuccessful because of conversion to material containing small amounts of phosphine oxide(s) formed via a redox reaction involving water. The triphosphine trioxide [(HOCH2)2P(O)(CH2)2]2P(O)CH2OH was readily isolated from an in situ solution of II by treatment with aqueous H2O2.