REDUCTIVE REMOVAL OF HALOGEN BY THIOLATES FROM 1-HALOCYCLO-PROPYL SULFIDES

Abstract

Nucleophilic substitution of cyclopropyl halides or tosylates is often accompanied by ring rupture, but this can be prevented by the presence of an electron releasing substituent in α-position (NR₂, OR, SR). Alkylthio and arylthio groups are particularly effective in stabilizing intermediate cyclopropyl cations. These give with most nucleophiles e.g. alkoxide, azide, fluoride, in relatively rapid reactions good yields of substitution products.     

Synthesis,Complexes and Metal Extraction Ability of R1R2NC(X)NHP(Y)(0Ph)2

Abstract

The new 1,1-disubstituted 3-diphenoxy(thio)phosphoryl-(thio)ureas, R¹R²NC(X)NHP(0Ph)₂, HA, with X,Y = O,S, were synthesized by addition of secondary mines to the corresponding P-iso(thio)cyanates. This reaction is reversible if X,Y = S. (PhO)₂P(Y)Cl reacts with H₂NC(X)NR₂ in the presence of an HCl acceptor only if X,Y a 0. Side reactions are observed. Phosphorylated derivatives of biuret were isolated from such a reaction mixture.     

Peculiarities of the reaction of 2,2,6,6-tetramethylpiperidin-1-oxyl with Cp2TiEtCl

The reaction of 2,2,6,6-tetramethylpiperidin-1-oxyl (1) with Cp₂TiEtCl (2) has been studied. The consumption of1 and evolution of gaseous products (ethane, ethylene) proceed with autoacceleration. Increasing the1 : 2 molar ratio leads to inhibition of the autoacceleration. The fact that the yield of ethane is higher than that of ethylene indicates that the reaction proceedsvia S_R2 substitution of the ethyl group in Cp₂TiEtCl for radical1. The mechanism of the substitution is synchronous, A kinetic model of the reaction has been proposed and substantiated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2904–2908, December, 1996.     

Synthesis and Coordination Properties of Multifunctional Carbamoylmethyl Phosphonates

Abstract

Bifunctional carbamoylmethylphosphonates are useful extractants for lanthanide and actinide ions and the structural mechanics involved in extraction processes have been under study in our laboratory. We have recently prepared several new multifunctional ligands of the general types (RO)₂P(O)CH[C(O)NR₂][CH₂C(O)NR₂], [(RO)₂P(O)]₂CHCH₂C(O)NR₂ and [(RO)₂P(O)CHC(O)NEt₂]₂CH_2. The syntheses and characterization data for the new extractants will be described. The coordination chemistry of these ligands with lanthanide and actinide ions has been studied and crystal structure determinations for selected complexes will be shown. Lastly, liquid-liquid extraction distribution measurements for several ligands with lanthanide ions will be presented.     

REACTION OF SCHIFF BASE OF THIOHYDRAZIDES WITH P(NR2)3

Abstract

Three pathways were observed in the reactions of Schiff bases of Thiohydrazides with P(NR₂)₃. (a) MeS-R₂N exchange: MeS-C([dbnd]S)-NHN[dbnd]CHPh (1) reacted with P(NR₂)₃ led to new Schiff bases, R₂N-C([dbnd]S)-NHN[dbnd]CH = Ph (2). (b) Cleavage of C[dbnd]S bond and the formation of P[dbnd]S bond: H₂N-C([dbnd]S)-NHN[dbnd]CH = Ph (3) reacted with P(NR₂)₃ gave rise to the thiophosphoric amide. (Et₂N)₂P([dbnd]S)-NH-CH = N-N[dbnd]CH-Ph (4). (c) Formation of thiadiazole and triazole: Schiff bases 2a and H₂N(MeS)C = N-N[dbnd]CH-Ph (6) reacted with P(NR₂)₃ respectively and produced 5-dimethylamino-2-phenyl-2,3-(2H)-1,3,4-thiadiazole (5) and 5-methylthio-2-phenyl-2,3-(2H)-1,3,4-triazole (7).     

On the Reaction of Phosphorous Acid Esters with Nucleophiles in the Presence of Carbon Tetrachloride

Abstract

Esters of N-Phosphoryl phosphazenes are prepared by a modified Atherton-Todd reaction from di- and triesters of phosphorous acid, sodium azide, and carbon tetrachloride in high yields. The utilization of the two-component system trialkyl phosphite/ carbon tetrachloride for preparing phosphazenes, (RO)₃P[dbnd]NY (Y: PO(OR)₂, SO₂R, COR, CN), and dialkoxyphosphoryl compounds, (RO)₂P(O)X (X: NHR, NR₂, OPh, CN, F, NCO), is presented.     

From Disilene (SiSi) to Phosphasilene (SiP) and Phosphacumulene (PCN)

The generation of heavier double‐bond systems without by‐ or side‐product formation is of considerable importance for their application in synthesis. Peripheral functional groups in such alkene homologues are promising in this regard owing to their inherent mobility. Depending on the steric demand of the N‐alkyl substituent R, the reaction of disilenide Ar₂Si?Si(Ar)Li (Ar=2,4,6‐iPr₃C₆H₂) with ClP(NR₂)₂ either affords the phosphinodisilene Ar₂Si?Si(Ar)P(NR₂)₂ (for R=iPr) or P‐amino functionalized phosphasilenes Ar₂(R₂N)Si? Si(Ar)?P(NR₂) (for R=Et, Me) by 1,3‐migration of one of the amino groups. In case of R=Me, upon addition of one equivalent of tert‐butylisonitrile a second amino group shift occurs to yield the 1‐aza‐3‐phosphaallene Ar₂(R₂N)Si? Si(NR₂)(Ar)? P?C?NtBu with pronounced ylidic character. All new compounds were fully characterized by multinuclear NMR spectroscopy as well as single‐crystal X‐ray diffraction and DFT calculations in selected cases.     

Multifunctional iron thiocarboxylate complexes: synthesis,reactivity and structure of CpFe(CO)<Subscript>2</Subscript>SCO-3,5-C<Subscript>6</Subscript>H<Subscript>4</Subscript>(COCl)<Subscript>2</Subscript>

A controlled substitution reaction of the chlorine atoms of 1,3,5-benzenetricarbonyl trichloride by the organoiron fragment (CpFe(CO)₂S) has been achieved. The complexes CpFe(CO)₂SCO-3,5-C₆H₃(COCl)₂ (1), 1,3-[CpFe(CO)₂SCO]₂-5-C₆H₃COCl (2) and 1,3,5-[CpFe(CO)₂SCO]₃C₆H₃ (3) were prepared from the reaction of (μ-S _x )[CpFe(CO)₂]₂ (x = 3, 4) with 1,3,5-C₆H₃(COCl)₃ in a 1:1, 2:1, or 3:1 metal to ligand molar ratio. The reactions of (1) with amines, thiols, and carboxylic acids produce the trifunctional mono-iron complexes CpFe(CO)₂SCO-3,5-C₆H₃(COY)₂ [Y = NR₂ (4), SR (5), OCOR (4)]. The X-ray structure determination of (1) is reported.     

Alditols in Organophosphorus Chemistry. Synthesis of New Monomeric,Oligomeric and Bis-Spirophosphoranes

Abstract

New mono, bis and polyspirophosphoranes have been prepared condensing alditols with aminophosphines P(NR₂)₃.     

Zur Reaktion von Diphenoxyphosphorylchlorid mit N,N-disubstituierten Harnstoffen – Bildung von phosphorylierten Biuret-Verbindungen

Reaction of Diphenoxyphosphorylchloride with N,N-disubstituted Ureas – Formation of Phosphorylated Biuret Compounds N′,N′-disubstituted N-diphenoxyphosphorylureas, (PhO)₂P(O)? NH? CO? NR¹R² (R¹ = R² = Et, 1 ; n-Pr, 2 ; n-Bu, 3 ; i-Bu, 4 ; R¹ = Me and R² = Ph, 5 ) as well as phosphorylated biuret compounds, (PhO)₂P(O)? NH? CO? NH? CO? NR¹R² are obtained in the reaction of diphenoxyphosphorylchloride with N,N-disubstituted ureas and triethylamine. The biuret derivatives are formed via (PhO)₂P(O)NCO. Their yield rises if the reaction is carried out without amine. The X-ray crystal structure analysis of (PhO)₂P(O)? NH? CO? NH? CO? NPr₂, 8 , shows that dimers exist in the crystal with intermolecular as well as intramolecular hydrogen bonds. The framework formed by atoms P? N1? C1(O4)? N2? C2(O5)? N3(C3)C6 is planar. The existence of a rotation barrier along the bond C2–N3 was detected by NMR spectroscopy.     

Tin(IV) Tetrachloride Complexes with Bis-(Dialkylamino)phosphoryl Fluoride: A Multinuclear (119Sn, 31P, 19F,and 1H) NMR Characterization in Solution

The two octahedral complexes SnCl₄·2(O)PF(NR₂)₂ (R = Me or Et) were prepared from reaction of SnCl₄ with the ligand (R₂N)₂P(O)F in anhydrous CHCl₃. The new adducts have been characterized by elemental analysis, IR, and multinuclear (¹¹⁹Sn, ³¹P, ¹⁹F, and ¹H) NMR spectroscopy. The NMR data show that the adducts exist in solution as a mixture of cis and trans isomers with markedly different proportions. When compared with previously described hexamethylphosphoramide (HMPA) and trimethylphosphate (TMPA) analogues, our results indicate that the cis isomer is the predominant species in solution. Low temperature ³¹P and ¹¹⁹Sn NMR spectra show that the compounds partially dissociate in dichloromethane.     

Syntheses of Polyethers from Pentafluorobenzonitrile or Pentafluorobenzophenone and Flexible Diphenols

Cyanopentafluorobenzene (CPFB, pentafluorobenzonitrile) or pentafluoro‐benzophenone (PFBP) were polycondensed with long flexible diphenols at a 1∶1 feed ratio in the presence of K₂CO₃. A rather selective substitution of two C‐F groups was achieved with the formation of cyclic polyethers as the main products. Polycondensations of CPFB with flexible diphenols at 3∶2 feed ratio (a₂/b₃) yielded soluble multi‐cyclic polyethers by highly selective substitution of three C‐F groups. Yet, polycondensation at a feed ratio of 5∶2 gave a complex reaction mixture and substitution of all five C‐F groups was not observed. In all experiments, cyclization played a key role for the avoidance of gelation.     

Epoxidation of alkenes with tungsten catalysts immobilised on organophosphoryl macroligands

Organophosphorus ligands when grafted onto porous polymers are able to complex with peroxotungstic acid to give immobilised catalytic species for the epoxidation of alkenes with hydrogen peroxide. The macroligands described here contain the phosphoryl (OP) subunit and are related to phosphine oxides R₃PO, phosphonic, phosphinic or phosphoric acid amides RP(O)(NRR)₂, RR>P(O)NR₂ and PO(NR₂)₃, respectively. These different ligands were introduced in hydrophobic polystyrene and hydrophilic polymethacrylate resins of gel- or macroporous type. This allowed the study of the influence induced on the reactivity and on the selectivity of the epoxidation by the nature of the ligand and by the polar environment around the catalytic sites inside the polymeric beads.     

Eine neue Methode zur Darstellung von Silaheterocyclen durch Cycloaddition im System Heterobutadien/HSiCl3/NR3

A New Method for the Generation of Silaheterocycles via [4 + 1]-Cycloaddition Reaction in the System Heterobutadiene/HSiCl₃/NR₃ The reaction of trichlorosilane with tert. amines provides the anion SiCl₃^– (Benkeser type system). This system can be used as a simple accessible SiCl₂ synthon in certain cases. Thus [4 + 1]-cycloadditions of diazabutadienes in the system HSiCl₃/NR₃ lead to silacyclopentene derivatives. The reaction of 1,3-diaza-1,3-dienes with equimolar amounts of DBU and HSiCl₃ in THF gives the 1,4-diazasila-cyclopentene (CF₃)₂C–N=C(Ph)–N(^tBu)–SiCl₂ ( 2 a ) derivative only in one case [6], whereas in other cases hydrosilylation products are obtained. In (CF₃)₂CH–N=C(Ph)–N(^tBu)–SiCl₂F ( 3 a ), which is obtained from ( 2 a ) with wet toluene, the amidinate is bidentate and thus coordinating in a chelating fashion to the five-coordinate silicon atom. 1,4-diaza-1,3-dienes (DAD) give the [4 + 1]-cycloaddition products in all cases. Product distribution and yield are strongly influenced by the substituents, the nature of the solvent and the reaction conditions. All compounds have been characterized by NMR and mass spectroscopy. In five cases, the results of crystal structure determinations by X- ray diffraction are reported.     

Reactions of Chlorosulfanyl Derivatives of Cyclobutanones with Different Nucleophiles

The reactions of 3‐chloro‐3‐(chlorosulfanyl)‐2,2,4,4‐tetramethylcyclobutan‐1‐one ( 2 ) with N, O, S, and P nucleophiles occur by substitution of Cl at the S‐atom. Whereas, in the cases of secondary amines, alkanols, phenols, thiols, thiophenols, and di‐ and trialkyl phosphates, the initially formed substitution products were obtained, the corresponding products with allyl and propargyl alcohols undergo a [2,3]‐sigmatropic rearrangement to give allyl and allenyl sulfoxides, respectively. Analogous substitution reactions were observed when 3‐chloro‐3‐(chlorodisulfanyl)‐2,2,4,4‐tetramethylcyclobutan‐1‐one ( 3 ) was treated with N, O, and S nucleophiles. The reaction of 3 with Et₃P led to an unexpected product via cleavage of the S? S bond (cf. Scheme 13). In the reactions of 2 with primary amines and H₂O, the substitution products react further via elimination of HCl to yield the corresponding thiocarbonyl S‐imides and the thiocarbonyl S‐oxide, respectively. Whereas the latter could be isolated, the former were not stable but could be intercepted by MeOH (Scheme 4) or adamantanethione (Scheme 5). The structures of some of the substitution products were established by X‐ray crystallography.     

A DFT Study on the Mechanism of Rh2II,II‐Catalyzed Intramolecular Amidation of Carbamates

The potential‐energy surfaces of the reactions of dirhodium tetracarboxylate (Rh₂^II,II) catalyzed nitrene (NR) insertion into C H bonds were examined by a DFT computational study. A pure Becke exchange functional (B88) rather than a hybrid exchange functional (B3, BHandH) was found to be appropriate for the calculation of the energy difference between the singlet and triplet Rh₂^II,II–NH nitrene species. Rh₂^II,II–NR¹ (R¹=(S)‐2‐methyl‐1‐butylformyl) is thermodynamically more favorable with a free energy lower than that of Rh₂^II,II–N(PhI)R¹. The singlet and triplet states of Rh₂^II,II–NR¹ have similar stability. Singlet Rh₂^II,II–NR¹ undergoes a concerted NR insertion into the C H bond with simultaneous formation of the N H and N C bonds during C H bond cleavage; triplet Rh₂^II,II–NR¹ undergoes H atom abstraction to produce a diradical, followed by subsequent bond formation by diradical recombination. The singlet pathway is favored over the triplet in the context of the free energy of activation and leads to the retention of the chirality of the C atom in the NR insertion product. The reactivities of the C H bonds toward the nitrene‐insertion reaction follow the order tertiary>secondary>primary. Relative reaction rates were calculated for the six reaction pathways examined in this work.     

Kinetics and Mechanism of Co Substitution by Phosphites of Co4(CO)12

Abstract

The otherwise very fast CO substitution of Co₄(CO)₁₂ by P(OMe)₃ and P(OEt)₃ in aprotic solvents, affording phosphite-monosubstituted products was retarded by the use of CHCI₃ as solvent. This made it possible to investigate these reactions by conventional methods. Kinetic data were obtained by following changes in IR spectra during reaction. The rates show predominantly a ligand-dependent pathway, with the usual two-term rate law, rate = (k₁ + k₂ [P(OR)₃])C₄(CO)₁₂. It is suggested that the rates are retarded in protonic solvents by decreasing the nucleophilicity of phosphites due to a hydrogen bonding interaction between the H atom of CHCI₃ and the O atoms of the ligands.     

CH3S与HCS双自由基反应的密度泛函理论研究

应用量子化学从头算和密度泛函理论(DFT)对CH₃S与HCS双自由基单重态反应进行了研究. 在MPW1PW91/ 6-311G(d,p)水平上优化了反应通道上各驻点(反应物、中间体、过渡态和产物)的几何构型, 用内禀反应坐标(IRC)计算和频率分析方法对过渡态进行了验证. 在QCISD(t)/6-311＋＋G(d,p)水平上计算各物种的单点能, 并对总能量进行了零点能校正. 研究结果表明, CH₃S与HCS反应为多通道反应, 有4条可能的反应通道, 反应物首先通过S…S弱相互作用形成具有竞争反应机理的五元环硫-硫偶合中间体a和链状硫-硫偶合中间体c, 再由此经过氢迁移、离解、异构化等不同机理得到主要产物P1 (2CH₂S), 次要产物P2 (CH₃SH＋CS), P3 (CH₄＋CS₂)和P4 [CH₂(SH)CSH]. 根据势能面分析, 所有反应均为放热反应, 生成P1的反应热为－165.55 kJ•mol^－1. 通道R→a→TSa/b→b→P1为标题反应的主通道, 其速控步骤a→TSa/b→b在200～2000 K温度区间内的速率常数可以表示为k₁^CVT/SCT＝1.75×10¹⁰T^0.65exp(－907.6/T) s^－1. P3及P4的生成需要越过很高的活化能垒, 是动力学禁阻步骤, 但在反应体系中加入合适催化剂, 改变其反应机理, 有可能使生成CH₂(SH)CSH, CH₄及CS₂的反应易于进行.     

Synthesis and Characterization of a Novel Phosph(V)azane-Platinum(II) Complex

The substitution reaction of bis(anilino)phosphine oxide (C ₆ H ₅ NH) ₂ P(O)H (1) with trans-PtCl ₂ (SEt ₂ ) ₂ yields the novel unprecedented phosph(V)azane-platinum complex cis-Pt(SEt ₂ ) ₂ Cl[HNPhP(O)NPh(HNEt ₃ )] (3). In this reaction, the bis(anilino)phosphine oxide undergoes P–H activation and a Pt(II)–P(V) bond instead of Pt–N bond forms. ³¹ P NMR spectra readily distinguish between the “N” and “P” bonding modes. The reaction requires the presence of triethylamine (TEA) as a base in order to deprotonate the phosphazane ligand and is separated as Et ₃ NH⁺Cl^?, whereas HTEA⁺ exists in the final product 3 and is acting as charge balancing and H-bond structure directing agent. The products have been fully characterized by means of IR; MS; UV-Vis; and ¹ H, ¹³ C, and ³¹ P NMR spectroscopy.     

Synthesis and characterization of a new cyclic phosph(V)azane ligand [(C6H5N)P(O)H]2 and its zinc(II) complex

The new cyclic phosph(V)azane ligand [(C₆H₅N)P(O)H]₂ (2) is obtained from the reaction between PCl₃ and PhNH₂ in toluene followed by controlled hydrolysis of the product in an H₂O–CHCl₃ solution. Compound 2 is the first example of P(V) dimer [(µ-NC₆H₅)P(H)=O]₂, a P₂N₂ ring with two P(O)H moieties. The reaction of 2 with ZnCl₂ in a molar ratio of 1?:?1 in tetrahydrofuran yields the cyclophosph(V)azane complex Cl₂Zn[(C₆H₅N)P(O)H]₂ (3) in which Zn–O bonds form directly between a cyclic phosph(V)azane ligand and Zn(II). The products have been characterized by infrared, multinuclear (¹H, ³¹P, ¹³C) NMR, mass spectrometry, and elemental analysis.