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New applications of methods leading to anhydrides RR′P(O)OSO2R″ (1) are described: a) Reaction of acids RR′P(O)OH (2) with sulfonic imidazolides. b) Reaction of phosphorus imidazolides 4 with sulfonic acids and sulfonic anhydrides. New Methods of synthesis of anhydrides 1 have been developed. c) Reaction of phosphorus acid silyl esters RR′P(O)OSiMe3 (9) with methanesulfonic and trifluoromethanesulfonic anhydrides. d) Reaction of bis(trimethylsilyl) tert-butyl-phosphonate (10) with methanesulfonic acid leading to t BuP(O)(OSO2Me)2 (11). e) Reaction of stannyl phosphate (EtO)2P(O)OSnMe3 (15) with methanesulfonic anhydride. f) Reaction of phosphorus acid silyl esters 9 with trimethylsilyl trifluoromethanesulfonate. All methods result in high yields and can be adapted to a variety of anhydrides 1 derived from phosphoric, phosphonic, and phosphinic acids on the one hand and methanesulfonic, trifluoromethanesulfonic acids and sulfuric monoimidazolide on the other. Phosphonium intermediates have been demonstrated by low temperature FT 31P NMR spectroscopy for reaction b) and c). The anhydrides 1 are readily converted into imidazolides 4 by the reaction with N-(trimethylsilyl)imidazole which proceeds via two distinct phosphonium intermediates. With neutral and weakly basic nucleophiles, the anhydrides 1 behave as phosphorylating agents. Anhydride aus Sauren des Phosphors und des Schwefels, 2. Gemischte Anhydride von Phosphor-, Phosphon- und Phosphinsauren mit Sulfonsauren und Schwefelsaure-monoimidazolid. Neue Synthesen, neue Verbindungen und ihre Eigenschaften als Phosphorylierungsmittel Es werden neue Anwendungen der Methoden, die zu Anhydriden der Struktur RR′P(O)OSO2R″ (1) fuhren, beschrieben: a) Die Reaktion von Sauren RR′P(O)OH (2) mit Sulfonsaure-imidazoliden. b) Die Reaktion von Imidazoliden 4 von Sauren des Phosphors mit Sulfonsauren und Sulfonsaure-anhydriden. Neue Methoden zur Synthese von Anhydriden der Struktur 1 wurden entwickelt. c) Die Reaktion von Trimethylsilylestern von Sauren des Phosphors RR′P(O)OSiMe3 (9) mit Methansulfonsaure- und Trifluormethansulfonsaure-anhydriden. d) Die Reaktion von tert-Butylphosphonsaure-bis(Trimethylsilylester) (10) mit Methansulfonsaure zu tBuP(O)(OSO2Me)2 (11). e) Die Reaktion des Stannylphosphats (EtO)2P(O)OSnMe3 (15) mit Methansulfonsaure-anhydrid. f) Die Reaktion von Trimethylsilylestern 9 von Sauren des Phosphors mit Trifluormethansulfonsaure-trimethylsilylester. Alle Methoden ergeben hohe Ausbeuten und konnen an die Vielzahl der Anhydride 1 aus Phosphor-, Phosphon- und Phosphinsauren einerseits und Methansulfonsaure, Trifluormethansulfonsaure und Schwefelsaure-monoimidazolid andererseits angepast werden. Fur die Reaktionen b) und c) konnten durch Tieftemperatur-FT-31P-NMR- Spektroskopie Phosphonium-Zwischenstufen nachgewiesen werden. Die Anhydride 1 lassen sich durch Umsetzen mit N-(Trimethylsilyl)imidazol leicht in Imidazolide 4 uberfuhren; diese Reaktion lauft uber zwei verschiedene Phosphonium-Zwischenstufen. Die Anhydride 1 wirken gegenuber neutralen oder schwach basischen Nucleophilen als Phosphorylierungsmittel.

The halogenation of phenyl-and o-methoxyphenyl-o-phenylene phosphites (1b, 1c) gives at low temperature pentacoordinated dihalogenophosphoranes 4a, 4b, 5a, 5b. They are stable at room temperature with the exception of 5b. Even at-100°C 5b slowly gives a bromospirophosphorane 3b by breaking the ether linkage. The primary formed phosphorane is in an equilibrium with the phosphoniumsalt; both phosphorus compounds are proved with 31P n.m.r. spectroscopy. Die Halogenierung von Phenyl-und o-Methoxyphenyl-o-phenylenphosphit (1b, 1c) fuhrt bei tiefen Temperaturen zu pentakoordinierten Dihalogenophosphoranen 4a, 4b, 5a, 5b, die beim Erwarmen auf Raumtemperatur mit Ausnahme von 5b stabil sind. Aus 5b entsteht bereits bei-100°C langsam unter Etherspaltung ein Spirophosphoran 3b. Das primar gebildete Phosphoran liegt mit dem Phosphoniumsalz im Gleichgewicht vor; beide Phosphorverbindungen sind NMR-spektroskopisch nachweisbar.

The thiocyanation of organophosphorus compounds containing >P(X)H functional group (X = O, S) has been reinvestigated. The reaction wa shown to be highly stereospecific and proceeds with the retention of configuration at P via the thiocyanidate >P(O)SCN structure. The thiocyanidates rearrange into the isothiocyanidates >P(O)NCS with a rate of depending on structure of substrates and reaction conditions. The thiocyanation reaction of dialykl phosphite and their structural analogues offers an excellent route to the isothicyanidates >P(X)NCS and in some cases also to the thiocyanidates >P(X)SCN.

Optically active t-butylphenylphosphinothiocyanidate Bu t PhP(O)SCN 3 and t-butyl-O-methyl-phosphonothiocyanidate Bu t (MeO)P(O)SCN 7 have been prepared by condensation of the corresponding sulphenyl chlorides > P(O)SCl with trimethylsilylcyanide and isomerised into optically active t-butyl-O-methyl-phos-phonoisothiocyanidates Bu t (MeO)P(O)NCS 8 . Chirality at P in and the optical purity of the chiral phosphino (phosphono) thiocyanidates and isothiocyanidates have been determined by chemical correlations. It has been demonstrated that the thiocyanate ion and amine catalysed thiocyanidate-isothiocyanidate isomerisation > P(O)SCN → > P(O)NCS occurs stereospecifically with inversion of configuration at the P center. This result can be rationalized by postulation of a phosphorane intermediate, formed by nucleophilic attack of the SCN - anion on phosphorus, in which thiocyanate and isothiocyanate groups occupy apical positions. In connection with these studies a number of novel optically active phosphorylated derivatives of carbonic acid, > P(O)NHCSNHR, > P(O)NCCl 2 , > P(O)NCO and > P(O)NHCOOBu t , have also been synthesised.

The reaction of a trialkyl phosphite with trimethylsilyl iodide, which leads to O -trimethylsilyl esters of alkylphosphonic acid, has been shown to involve several steps, all of which are defined. The first step is the formation of the iodophosphite, involving a four centre mechanism in which P III plays the role of electrophile. This is in contrast to the analogous reaction of phosphates with alkyl halides (the Arbuzov reaction) which begins with nucleophilic attack of the phosphorus.

Oxophosphoranesulphenyl chlorides react readily with dialkyl phosphites giving, in high yield, simple and mixed sym-thiopyrophosphates (RO)2P(O)–S–P(O)(OR′)2, uncontaminated by any catalyst for the ready isomerization into the unsymmetrical isomers, P(O)–O–P(S), which has marred earlier procedures. The reaction involves nucleophilic attack by the phosphorus atom on the sulphur atom of the sulphenyl chloride and formation of a quasiphosphonium complex. Some side reactions resulting from the great reactivity of sym-monothiopyrophosphates are also described.

The reaction of triorganosilylsulfenyl halides R3SiSX (R  Ph, Et; X  Cl, Br) with carboncarbon double bonds, trialkyl phosphites, and organometallic reagents have been studied. With the first two nucleophiles the course of the reactions differed from that with organosulfenyl chlorides because of nucleophilic attack of halide ion on silyl group.

We report the synthesis of the first optically active silyl esters of phosphorus hewing too centres of chirality : one on silicon and the other on phosphorus. Compounds we obtained of general formula : t-BuPhP(X)YSiαNpPhMe X,Y=0,0( 1 ): S, ( 2 ); Se, 0(3); S, 3(4); doublet, 0( 5 ) including 1 and 3 with optical activity located on Si, 2 and 5 with the activity on Si or P and on both these centras, 4 only racemic. Absolute configurations are determined. 31P and-29Si NMR spectra of these models and their trimethylsilyl analogues are reported. The triorganosilyl group is always preferentially bound to phosphorus through oxygen atom. Surprisingly, diastereotopio NMR chemical shifts exclude the fast 1,3 migration in esters 1 and 4 . 29Si NMR spectra correspond to a tetracoordinate silicon atom.

Catalytic activities of R(+) and racemic t-butylphenylphosphinothioic acids on the mutarotation of 2,3,4,6 tetramethyl-d-glucose are studied in benzene.

Special attention in this Laboratory has been recently given towards the chemistry of phosphorus-sulfur acids anhydrides RR1P(X)-O-SO2-R2 (X[dbnd]0, S, Se) 1.

Stable ionic 11 adducts, thought to be of the type [(Me2N)3POSiMe3]+X− have been isolated from the interaction of HMPT with the halides Me3SiX (X  Br or I). Conductometric studies show that the equilibrium for formation of these adducts in CH2Cl2 lies well over to the products for X  Br or I, but for X  Cl the equilibrium lies close to the reactants. The known kinetic characteristics of reaction involving HMPT-catalysed racemisations or substitutions of silicon halides can be interpreted in terms of the formation of such phosphonium intermediates.

A novel highly efficient synthesis of sym-tetra-alkyl monothio- and monoseleno-pyrophosphates (RO)2P(O)XP(O)(OR′)2(X = S,Se) based on the condensation of dialkoxyoxophosphorane-sulphenyl or -selenenyl chlorides (RO)2P(O)XCl (X = S,Se) with dialkyl trimethylsilyl phosphites (RO)2POSiMe3(9) is described. Remarkably selective reaction of a O,O′-dialkyl O″-trimethylsilyl selenophosphate (RO)2P(Se)OSiMe3(13) with sulphuryl dichloride in the presence of an equimolar amount of a phosphite (9) leads to the formation of sym-monoselenopyrophosphates in excellent yield. A new rearrangement in phosphorus chemistry, sym-monoselenopyraphosphates (11) to asym-monoselenopyrophosphates (12), has been observed.

Dialkylthioxaphosphoranesulfenyl chlorides and bromides can be conveniently prepared in the reaction of the corresponding thioamides with hydrogen chloride generated in situ with trimethylsilyl chloride and ethanol. Stability of the chlorides and bromides obtained by this method is high and the yields are quantitative.

Low temperature 31P n.m.r. spectroscopy and chemical data have been applied to elucidate the mechanism of the Arbuzov-type reaction between phosphites and halogens. Simple and substituted trialkyl, alkyl 1,2-phenylene, and trisilyl phosphites have been allowed to react with chlorine, bromine, and iodine. In some cases intermediate halogenophosphonium salts (2) and in others halogenophosphoranes (3) are observed which then decompose into the corresponding pure highly reactive phosphorohalidates (4). It was possible to prepare stable phosphonium salts from halogenophosphonium salts (2) and halogenophosphoranes (3).

A study is described of the reaction of trimethylbromosilane and trimethyliodosilane with various esters of phosphorothioic and phosphoroselenoic acids of general structures (RO) 2 (RY)P=O (I) and (RO) 3 P=Y (II) (Y = S or Se, R = alkyl). The reaction results in replacement of the R groups by trimethylsilyl groups. No S -trimethylsilyl and Se -trimethylsilyl substituted esters were found among the products. Thus the displacement of the O -R group in II as well as the replacement of S -organyl or Se -organyl groups in I both lead to the corresponding O -trimethylsilyl isomer containing thiophosphoryl or selenophosphoryl groups. The following sequence of reactivity of the ester groups was observed: Download full-size image The process involves initially the reversible formation of a phosphonium salt intermediate in a fast step, followed by slow dealkylation. It was shown by low temperature 31 P FT-NMR studies that in the reaction of trimethyliodosilane with an ester bearing a P=O phosphoryl group, the equilibrium for the phosphonium salt formation lies well over towards the intermediate and so the intermediate can be observed directly. These mechanistic proposals were confirmed by conductance studies on the reaction system and by investigation of the stereochemical course of the corresponding reaction of an optically-active model thiophosphonate. In some cases the reaction of the halosilanes with the phosphates takes a selective course which allows the reaction to be used as a convenient route to O -silyl substituted esters of phosphorothioic or phosphoroselenoic acids.

Reactions of hexamethyldisilathiane with oxophosphoranesulfenyl chlorides, oxophosphorane sulfenates and bis-phosphoranyldisulfides were studied. These processes lead to mono o-silyl thionesters of phosphorus. The mechanistic pathways are discussed.

We describe new highly effective methods leading to compounds of general formula 1 and 2 including chiral diaste-reoisomeric systems 1, (Y=S, X=Cl) containing the asymmetric phosphorus center. Some aspects of the reaction between organophosphorus dithioacids and halogens are also discussed.

In order to throw light on the possible role of positively charged tetra-coordinate silicon intermediates in the racemization of α-NpPhMeSiCl ( 1 ) induced by uncharged nucleophiles two sets of kinetic studies have been carried out. In the first the rates of two reactions namely racemization of 1 catalysed by (PhO) 2 (Me 3 SiO)PO ( 2 ) and transsilylation of 2 with 1 , which take place together and are believed to involve the same intermediate were determined; the transsilylation was found to be faster than the racemization, and involved transient formation of an optically active product. In the second the racemization of 1 catalysed by HMPT in various CCl 4 /CH 2 Cl 2 mixtures was studied; the rate was found to increase markedly with increase in the dielectric constant of the medium. The results of both sets of experiments were consistent with a mechanism involving a silyloxyphosphonium cation intermediate.

The oxidative addition of thiocyanogen to triphenylphosphine has been investigated by 31P NMR spectroscopy showing the formation of the isothiocyanatophosphonium salt 8. The analogous reaction between thiocyanogen and alkyl o-phenylene phosphites 7 leads to diisothiocyanatophosphoranes 9. The same products were prepared via ligand substitution from the corresponding chlorophosphonium salt 12 and alkyldichloro-o-phenylene phosphoranes 13 by the action of potassium thiocyanate in the presence of 18-crown-6-ether or more conveniently using lead thiocyanate. The phosphonium salt 8 and phosphoranes 9 were employed as convenient novel reagents for converting hydroxy groups into thiocyanate and isothiocyanate functions with high stereoselectivity under very mild conditions. The efficient synthesis of acylisothiocyanales RCONCS, R2P(O)NCS and R2P(S)NCS via addition of thiocyanogen to mixed anhydrides is of special interest.

The reaction of phosphorous hexamethyltriamide with trimethylsilyl iodide or bromide provides a convenient synthesis of the corresponding N,N,N',N'-tetramethylphosphorodiamidous halide. Low temperature 31P NMR studies gave evidence of the formation of a phosphonium salt-type complex with direct P-Si bonding in the first step of the reaction. Analogous phosphonium salt intermediates involving P-P bonds were found to be involved in some ligand exchange process between two tricoordinated phosphorus species.

Die Synthese von Phosphorsaure-monoathylester, -diathylester und -triathylester (1–3) sowie von Phenylmethanphosphonsaure-monoathylester und -diathylester (4, 5) durch selektive Alkylierung der Orthophosphorsaure und Phenylmethanphosphonsaure mit Triathylphosphit wird beschrieben. Selective Alkylation of Polybasic Phosphoric Acids with Trialkyl Phosphite The synthesis of mono-, di-, and triethyl phosphate (1–3) as well as of mono- and diethyl phenylmethane phosphonate (4, 5) by selective alkylation of orthophosphoric and phenylmethane phosphonic acid with triethyl phosphite is described.

Optically active pyrophosphonothionates (II, III and IV) have been obtained in the reaction between optically active O-ethyl ethylphosphonothioic acid (I) and 2-chloro-2-oxo-5,5-dimethyl-1,3,2-dioxaphosphorinan, diethyl phosphorochloridate and O,O-diethyl phosphorochloridothionate respectively. It has been found that alkaline hydrolysis of these anhydrides occurs with full inversion of configuration at the thiophosphoryl centre. The reaction is discussed from the point of view of stereochemistry and the reaction mechanism.

2-Thiono-5,5-dimethyl-1,3,2-dioxaphosphorinan 1 treated with nitrosyl chloride yields a mixture of asymmetric 2 and symmetric 3 dithiopyrophosphates. Reinvestigation of the reaction of nitrosyl chloride with diethyl thiophosphite showed that, in addition to tetraethyl thiopyrophosphate, the corresponding dithiopyrophosphates are also formed. A mechanism is suggested for the reactions investigated, with nitrosyl chloride as an ambident nucleophile.

Die Alkoholyse von (Thiophosphorigsaure-O-athylester)-(phosphorsaurediathylester)anhydrid fuhrt zu gemischten Thiophosphorigsaure-O.O-dialkylestern und Phosphorsaure-diathylester. Thiophosphorigsaure-O-athylester-O-butylester ist auch durch Umsetzung von Phosphorigsaure-athylester-butylesterchlorid mit Schwefelwasserstoff erhaltlich.

Phosphorsaure-dialkylester, Carbonsauren und Sulfonsauren lassen sich durch Umsetzung mit Tetraalkylestern des Phosphorsaure-phosphorigsaure-anhydrids phosphorylieren. In allen Fallen entstehen die Anhydride des Phosphorsaure-dialkylesters und Dialkylphosphit mit hoher Ausbeute.

The reaction of (−)- and (+)-O-ethyl ethylphosphonothioic acid (I) with phosphorus pentachloride has been shown to give optically active O-ethyl ethylphosphonochloridothionate (II) in high yield. For establishing the relative configuration and degree of stereospecificity of (II) use was made of the pyrophosphonothionates, prepared from I and II. The mechanism of the reaction is discussed.

The results of stereochemical and product studies on the chlorination of phosphorus thionesters are rationalized in terms of phosphonium and five-co-ordinate intermediates which in the case of thionophos-phonates and cyclic five-membered thionophosphates undergo nucleophilic ligand exchange.xs

Racemic and optically active S-sulphonylphosphinothioates R-SO2-S-P(O)Bu'Ph and dithioates R-SO2-S-P(S)Bu'Ph (R [dbnd] Me, p-tolyl) have been prepared for the first time by the reaction of the corresponding acids Bu'PhP(S)SH (X [dbnd] O,S) of their salts with sulphonylating reagents RSO2-Y (Y [dbnd] Cl, O-SO2R, triazolide).

The thioxophosphoranesulphenyl bromides (1) act as ambident electrophiles towards alkenes and react, depending on the structure of the alkene, to give either the normal addition products –SC(R1)(R2)CR3(R4)(Br) or 1,2-dibromides and -disulphides.

Ambident anions derived from phosphorus monothio acids have been glycosylated by 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl-, 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl- and 2,3,4-tri-acetyl-α-D-xylopyranosyl bromides, yielding β-S-glycosyl- and /gb-O-glycosylthioates. The S/O ratio of the glycosylated phosphorothioates depends markedly on the salt used. Ammonium salts favour the formation of S-derivatives, whereas silver salts give mainly O-derivatives. O-Glucosyl phosphorothioate undergoes thermal isomerisation to S-glucosyl phosphorothioate, with retention of configuration at the glycosylic centre. The implications of this stereochemical result are briefly discussed.