2-Cyanoacrylates as reagents in heteroatomic synthesis (a review)

Several types of addition reactions to the CC bond of alkyl 2-cyanoacrylates, CH₂C(CN)COOR ( 1 ), are considered. The first examples deal with addition of CH-Acids (p K _a less than 13) and of H₂S in the presence of catalytic amounts of strong amines, also of mercaptans, thiocarboxylic, and thiophosphoric acids. P-Sulfenylchlorides and acidic phosphites add irreversibly at 20°C to form addition products in accordance with the distribution of charges in 1 . HCl reversibly adds to 1 and to the acid chloride CH₂C(CN)COCl ( 2 ). Alcohols and H₂O also add reversibly to the acid CH₂C(CN)COOH ( 3 ) and to esters of 1 to transform 1 and 3 into polymers. Triethylsilane in the presence of CF₃COOH ( 4 ) reduces the CC bond of 1 and 3 to the corresponding saturated derivatives. The second set of examples involves reactions of 1 with P-III compounds in the presence or absence of 4 . Ph₃P as well as other weak nucleophiles reversibly add to 1 in the absence of 4 to cause instant polymerization. However, 4 protonates an initially formed zwitter-ion in the reaction of 1 with Ph₃P,(EtO)₂PCl,Ph₂PCl and thiourea to afford stable addition products. IR spectroscopy reveals the formation of H-complexes of 4 with the CN and COOR groups of 1 , which stimulates the addition of the weak nucleophile (o-C₆H₄O₂)PCl to the CC bond of 1 . This reagent does not react with 1 in the absence of 4 . Strong nucleophiles, Alk₃P, and (Et₂N)₃P in excess irreversibly add at 20°C to 1 to form zwitterions, which specifically react with PhNCO to give stable products. 1,3,2-Dioxaphospholes react with 1 either to form spirophosphoranes or 2-cyano-3-phosphoranylpropionates.     

Darstellung und Eigenschaften von Tris(diphenylamino)-phosphin

Preparation and Properties of Tris (diphenylamino) Phosphine The synthesis and some properties of tris(diphenylamino)phosphine are described. Displacement of the chlorine atom is readily achieved by reaction of (Ph₂N)₂PCl with Ph₂NSime₃. Thus tris(diarylamino)phosphine (Ph₂N)₃P is obtained almost in quantitativ yield. The aminolysis reaction of PCl₃ or (Ph₂N)₂PCl with Ph₂NH gives also (Ph₂N)₃P. The properties and structure of the phosphine on basis of spectroscopical and X-ray investigations are discussed.     

Reactivity of Geometric Isomers of (–)-Dichloropyridine(methyl-para-tolylsulfoxide)platinum(II) by Optical Rotatory Dispersion

The reactions of the optically active geometric isomers of the platinum(II) complex (–)-[Pt(Me-p-TolSO)(Py)Cl₂] with several nucleophilic reagents (Py, Ph₃PS, Ph₃P, Ph₃As, and Me₂SO) were studied by optical rotatory dispersion, IR spectroscopy, and ¹H and ³¹P NMR spectroscopy. A mechanism for the reaction is proposed.     

Single-crystal esr study of x-irradiated 2-chloro-2,2'-spirobis (1,3,2-benzodioxaphosphole): phosphorus in an octahedral geometry with the unpaired electron and chlorine in axial positions

X-irradiation of a single crystal of 2-chloro-2,2'-spirobis(1,3,2-benzodioxaphosphole) yields the oriented P^VI radical anion formed by electron capture. Directions of maximum values of the magnetic hyperfine tensors of ³¹P, ³⁵Cl, and ³⁷Cl are coincident and oriented along the P—Cl linkage, indicating an octahedral structure with the unpaired electron and chlorine in axial positions.     

Reduction of Phosphine Oxide by Using Chlorination Reagents and Dihydrogen: DFT Mechanistic Insights

Extensive DFT calculations provide detailed mechanistic insights into the metal-free reduction of phosphine oxide Ph₃P=O by using chlorination reagents O=CClX (X=COCl, Cl, OCCl₃ and Ph) and H₂. Fast electrophilic attack to the P=O group oxygen atom is favored by exergonic CO₂ release to form phosphonium Ph₃PCl⁺ and chloride Cl⁻, which may slowly cleave H₂ by an unstable HPh₃PCl complex yielding Ph₃PH⁺ and Cl⁻ ions in solution. Moderate heating is required to accelerate the slow H₂-activation step and to eliminate HCl to form phosphine Ph₃P instead of Ph₃PH⁺Cl⁻ salt as the desired product. Though partially quenched by Ph₃P (and reactant Ph₃P=O if present), borane B(2,6-F₂C₆H₃)₃ can be still combined with Cl⁻ and Ph₃P as reactive frustrated Lewis pair (FLP) catalysts.     

Nucleophilic transformations of cyclic phosphate triesters

Reactions of cyclic phosphate triesters, such as 2-ethoxy-1,3,2-dioxaphospholane 2-oxide, with Grignard reagents such as phenyl-, alkyl-, ethynyl-, and allyl-magnesium halides result in ring opening leading to the corresponding phosphonates, via nucleophilic attack of carbon on the phosphorus atom. Treatment of 2-ethoxy-1,3,2-dioxaphospholane 2-oxide with sodium borohydride yields ethyl 2-hydroxyethyl phosphite. This reaction is exclusive for the five-membered cyclic system: under these conditions acyclic phosphate triesters, such as triethyl phosphate, are unreactive and the analogous six-membered ring system, 2-ethoxy-1,3,2-dioxaphosphorinane 2-oxide reacts only partially to give unidentified phosphate esters and traces of phosphonate products. Both compounds were inert to NaBH₄.     

Zur Reaktion von Triphenylphosphan mit Thionylchlorid

Triphenylphosphine reacts with thionyl chloride to give [Ph₃PCl]Cl, Ph₃PO and Ph₃PS the formation of the anions S(O)Cl and SCl being discussed; the crystal structure of [Ph₃PCl]Cl · S(O)Cl₂ is reported.     

Isolation and Characterization of intermediate in the Synthesis of α-Fluorodiesters

The anion [(EtO)₂P(O)CFCO₂Et]^?Li⁺, pregenerated from its precursor diethyl (carboethoxyfluoromethyl)phosphonate (EtO)₂P(O)CFHCO₂Et and n-butyllithium, was added via syringe to a THF solution of ethyl oxaiyl chloride to yield an acylated phosphonate (EtO)₂P(O)CF(COCO₂Et)CO₂Et. In situ reaction with Grignard reagents RMgX produces the α-fluorodiesters (E,Z)-R(CO₂Et)C=CFCO₂Et in good yields. In contrast, addition of ethyl oxalyl chloride to a THF solution of diethyl (carboethoxyfluoromethyl)phosphonate anion gives an isolated intermediate (EtO)₂P(O)CFCO₂Et(CO₂Et)C=CFCO₂Et. Subsequent reaction of this isolated intermediate with Grignard reagents also affords a one-pot synthesis of the α-fluorodiesters with high E-stereoselectivity. The E-stereoselectivity increases when HMPT or DMPU is used as a cosolvent in the preparation of diethyl 2-fluoro-3-phenylfumarate (E,Z)-Ph(CO₂Et)C=CFCO₂Et.     

Reaction of the N,N-dimethylamide and methyl ester of 3-phenyl-3-chloro-2-ketopropionic acid with triphenylphosphine

Conclusions The dimethylamide of 3-phenyl-3-chloro-2-ketopropionic acid reacts with Ph₃P to give -(N,N-dimethyloxamoyl)benzyltriphenylphosphonium chloride. In the presence of methanol, this reaction gives dimethyl(phenylpyruvoyl)amide and Ph₃PO.2. The methyl ester of 3-phenyl-3-chloro-2-ketopropionic acid reacts with Ph₃P to give methoxycarbonylstyryloxytriphenylphosphonium chloride, which, upon heating in benzene at reflux, gives methyl -chlorocinnamate and Ph₃PO.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1395–1396, June, 1989.     

Reactions of Sulfenamides with Compounds of Trivalent Phosphorus

Chloro-dimethylamino-phenyl-p-tolylthio-phosphonium chloride 2 , dimethylamino-diphenyl-p-tolylthio-phosphonium chloride 3 , bis(diethylamino)-dimethylamino-p-tolylthiophosphonium chloride 4 and tert-butyl-dimethylamino-phenyl-p-tolylthio-phosphonium chloride 5 were prepared by the reaction of N,N-dimethylamino-p-tolylsulfenamide 1 with PhPCl₂, Ph₂PCl, (Et₂N)₂PCl and ^tBu(Ph)PCl, respectively. The reaction of N,N′-dimethyl-N,N′-bis(trimethylsilyl)urea 9 and N-methyl-N′-phenyl-N,N′-bis(trimethylsilyl)urea 10 with phenylsulfenyl chloride 6 or p-nitrophenylsulfenyl chloride 8 furnished the N-arylthio-N,N′-diorgano-N′-(trimethylsilyl)-ureas 11 – 14 . The reaction of 11 – 14 and of the previously known compounds 15 and 16 with MePCl₂, ClCH₂PCl₂, ^tBuPCl₂ and PhPCl₂ resulted in the formation of the 2-arylthio-2-chloro-1,2,3-triorgano-1,3,2λ⁵-diazaphosphetidin-4-ones 17 – 26 . 1,3-Dimethyl-2-(1,1,1,3,3,3-hexafluoro-2-propoxy)-2-phenyl-2-phenylthio-1,3,2λ⁵-diazaphosphetidin-4-one 29 and the 2-arylthio-1,3-dimethyl-2-(p-nitrophenoxy)-2-organyl-1,3,2λ⁵-diazaphosphetidin-4-ones 30 – 32 were obtained in the reactions of compounds 17, 24 and 27 with 1,1,1,3,3,3-hexafluoro-2-propanol or p-nitrophenol in the presence of triethylamine. The reaction of compound 21 with thiophenol in the presence of triethylamine resulted in a mixture of products, from which 1,3,4,5,7-pentamethyl-1,3,5,7-tetraaza-4λ⁵-phosphaspiro[3.3]heptan-2,6-dione 33 was isolated. The identity and structure of all the new compounds were established by ¹H-, ¹³C- and ³¹P-NMR spectroscopy and by elemental analysis. A possible mechanism of reaction of sulfenamides with compounds of trivalent phosphorus is discussed. For the compounds 5a, 32 and 33 X-ray structure analyses were conducted. The cation of compound 5a involves four-coordinate phosphorus (essentially tetrahedral geometry) and is a rare example of a P–S single bond in such a system (P–S 207.37(9) pm). In 32 the geometry at phosphorus is distorted trigonal bipyramidal, with axial positions occupied by oxygen and nitrogen atoms. In the spirophosphorane 33 the geometry at phosphorus is intermediate between trigonal bipyramidal and square pyramidal, with essentially planar four-membered rings.     

Reactions of Halides of Tervalent Phosphorus with Imines and -Diimines

Abstract

Isobutylidenebutylamine reacts with phosphorus trichloride in the presence of organic bases to give N-butyl-N-isobutenylamidodichloro-or bis(N-butyl-N-isobutenylamido)chlorophosphites depending on the ratio of reagents. Reasons are given in Eavour of the reaction beginning with the nucleophilic attack of the nitrogen atom of the imine on the electrondeficient phosphorus atom of the chloride. Reactions of ethyldichloro- and diethylchlorophosphites with benzylidenmethylamine produce 2-chloro- and 2-ethyl-2-oxo-1,4,2-diazaphospholanes respectively. Interaction of diethylchlorophosphite with benzylidenmethylamine in the presence of triethyphosphite results in the formation of diethyl. (N-methyl-N-α-diethylphosphonobenzylamido)phosphite. As a result of interaction of bis(diethylamino)chlorophosphine with NIN-dibutyl-2,3-butandiimine in the presence of triethylamine new compounds (2-diethylamino-1,3-dibutyl-4,5-dimethyl-1,3,2-diazaphospholane and 4,8-dibutyl-3,7-bis(diethylamino)-[3.3.01-bicyclooctadiene-l15) are obtained. The structure of the latter is proved by means of ¹H, ³¹ p NMR-spectroscopy, and a complete X-ray analysis. Alkyldichlorophosphines form phosphonium salts of 1,3,2-diazaphospholene structure with a-diimines and 2-chloro-1,3-dicyclohexyl-4-chloro-1,3,2-diazaphospholene resulting from the reaction of N,N-dicyclohexylethylenediimine with PCl₃. In this product the P-C1 bond is unusually long, which is confirmed by X-ray analysis. In the course of the interaction of tervalent phosphorus halides with α,β-unsaturated imines a new reaction has been discovered with the formation of 1,2-dihydro-1,2-azaphosphorines.     

Reaction of 2-chlorophenylacetylene with 2,2,2-trichloro-1,3,2λ5-benzodioxaphosphole

According to the ¹³C and ¹H NMR data (one-and two-dimensional spectra), o-chlorophenylacetylene reacts with 2,2,2-trichloro-1,3,2λ⁵-benzodioxaphosphole under mild conditions to give a mixture of diastereoisomeric 2,6-dichloro-4-(2-chlorophenyl)-1,2λ⁵-benzoxaphosphinin-2-ones differing in the configuration of the phosphorus atom and rotation of the o-chlorophenyl group about the C⁴-C_arom bond. Hydrolysis of that mixture leads to 6-chloro-4-(2-chlorophenyl)-2-hydroxy-1,2λ⁵-benzoxaphosphinin-2-one as a single stereoisomer.     

Ligating characteristic of an unstable phosphorus(III) derivative diphenylisothiocyanatophosphine; Synthesis and characterization of its chelates with transition metal ions

Summary Diphenylisothiocyanatophosphine prepared in CHCl₃ solution from Ph₂PCl and AgSCN yields stable complexes with MCl₂, Cu₂Cl₂, [Ni(Ph₃P)₂Cl₂] or [Cu(Ph₃P)₃Cl] which have the stoichiometry [MLCl₂], [M=Ni(1) or Cu(2)], [CuLCl](3), [Ni(Ph₃P)-(Ph₂PNCS)Cl₂](4) and [Cu(Ph₃P)(Ph₂PNCS)Cl](5) respectively characterized by physicochemical methods. The>PNCS moiety retains its entity in the complexes providing both P and S as chelating centres. The geometry of the complexes has been determined from magnetic susceptibility and electronic spectral measurements.     

Synthesis of 2-(perfluoroalkyl)ethyl potassium sulfates based on perfluorinated Grignard reagents

The first example of nucleophilic substitution with perfluoroalkyl Grignard reagents on the sp³ carbon centre is described. Thus, a series of organometals R_F-MgBr, prepared from perfluorinated alkyl iodides R_F-I with R_F = C₄F₉, C₆F₁₃, C₈F₁₇, C₁₀F₂₁ and C₁₂F₂₅, reacted with 1,3,2-dioxathiolane-2,2-dioxide to afford the corresponding 2-(perfluoroalkyl)ethyl magnesium sulfates, which were isolated after metathesis to the corresponding potassium salts. In the model reaction, perfluorohexylmagnesium iodide was reacted with methyl triflate yielding polyfluorinated alkane. The attempts to extend the reaction to 1,3,2-dioxathiane-2,2-dioxide were unsuccessful due to its inferior reactivity and only reduced polyfluoroalkane and the product of coupling were detected in the reaction mixture. Polyfluorinated sulfates are easily hydrolyzed with hydrochloric or triflic acid to the corresponding alcohols, which is an alternative to standard transformation of perfluoroalkyl iodides to 2-(perfluoroalkyl)ethanols. Quantum-chemical calculations of the PES of the reaction with both sulfur-containing heterocycles found that the failure of the reaction with 1,3,2-dioxathiane-2,2-dioxide is caused by higher activation energy of the process.     

2-chloro-2-thio-1,3,2-oxoazaphosphacyclohexane and its derivatives

Conclusions The authors have obtained 2-chloro-2-thio-1,3,2-oxoazaphos-phacyclohexane and studied its reactions with nucleophilic reagents.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 398–400, February, 1968.     

Zur Umsetzung des Zweikomponentensystems Triethylphosphit/Tetrachlorkohlenstoff mit wasserstoffhaltigen Nucleophilen 1. Die Reaktion mit Säureamiden

Reaction of the Two-component System Triethylphosphite/Carbon Tetrachloride with Nucleophiles Containing Hydrogen. 1. Reaction with Acyl Amides Acyl amides react with the two-component system triethylphosphite/carbon tetrachloride yielding N-acyl phosphazenes, (EtO)₃P?N? Ac. In this way (EtO)₃P?N? P(O)(OEt)₂, (EtO)₃P?N? CN, (EtO)₃P?N? C(O)Ph, and (EtO)₃P?N? SO₂Ph were prepared. Ethyl esters of phosphoric acid and trichloromethane phosphonic acid were obtained as by-products.     

Isosteviol acylphosphonates

A reaction of ent-16-oxobeyeran-19-oic acid (isosteviol) with an excess of PCl3 gives the corresponding acid chloride as a sole product. The latter reacts with trialkyl phosphites and dialkyl trimethylsilyl phosphites to yield acylphosphonates inert to nucleophilic reagents.     

The First Six-Membered “True” Heterocycle – Hydrogen-Bond-Assisted Ladder Formation in a KOCNPS Ring System

A ladder of alternating K₂S₂ and K₂O₂ rings exists in K[Ph₂P(S)NC(O)Ph]⋅MeOH, the first six-membered “true” heterocycle, in the solid state (see picture). A simple P–N bond-forming reaction between benzamide and Ph₂PCl gives the precursor Ph₂P(S)NHC(O)Ph, from which the potassium salt can be generated by reaction with KOtBu.     

The synthesis of bis(fulvalene)dicobalt hexafluorophosphate [(h5:h5′-C10H8)2 CoIII2][PF6]2

The organometallic compounds (Ph₃P)AuC(OMe)=NAr and [(EtO)(ArN=)C]₂ Hg can act as monodentate or as balentate ligand, respectively, towards another, different emtal atom (e.g. Ag and Rh).     

Reaction of diphenylthiophosphinous esters with diphenylchlorophosphine

Conclusions The reaction of ethyl diphenylthiophosphinite with Ph₂PCl leads to the formation of tetraphenyldiphosphine, ethyldiphenylphosphine Sulfide, and diphenylchlorophosphine sulfide. Phenyl diphenylthiophosphinite under drastic conditions undergoes isomerization to triphenylphosphine sulfide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 951–952, April, 1982.