Lothar Riesel

On the extension of the atherton-todd reaction to the 1-organyloxy 1-hydridobicyclophosphoranes

Abstract The 1-methoxy 1-hydridobicyclophosphorane 1 undergoes oxidation reaction with CCl 4 in basic solutions which allow the replacement of the hydrogen linked to phosphorus by several nucleophile groups. The same reaction carried out with the bicyclophosphorane 8 leads to a new compound 10 in which two P v atoms are included in a ten membered ring.

Zur disproportionierung der phenylfluorphosphane (C6H5)2PF und (C6H5)PF2

Abstract Ph 2 P-PF 2 Ph 2 has been identified by means 19 F- and 31 P- NMR spectroscopy as an intermediate product of the disproportionation of Ph 2 PF. The disproportionation is catalyzed by acids. The reaction mechanism is discussed. PhPF 2 disproportionates faster in solution in acetonitrile than neat, forming (PhP) 6 , instead of (PhP) 5 .

Fluoridolysis of N-phosphoryl phosphazenes and diphosphoryl compounds

Abstract The present work deals with the use of the adduct Et 3 N· n HF as fluorination agent for heteroatom bridged phosphorus compounds of the structure X 2 P(O)NPX 3 ( I ) ( X Cl, Ph, PhO, EtO, NEt 2 ) and X 2 P(O) Y P(O) X 2 ( II ) ( X Cl, PhO, EtO, NEt 2 ; Y NH, NMe, O). Facilities and limits of the substitution of fluoride for phosphorus-bonded groups X are shown. The mechanism of the reaction and therewith the type of resulting products depends on the concentration of protons in the reaction medium as well as the concentration and nucleophilic force of the free fluoride ions. Furthermore, the temperature, the base used and the presence of other nucleophiles competing with fluoride play an important role. Both N-phosphoryl phosphazenes ( I ; X Cl, Ph, PhO, NEt 2 ) and imidodiphosphoric acid derivatives ( II ; X =Cl, PhO; Y NH) give defined X /F replacement products. Under certain conditions pentafluorophosphates of the structure [F 5 P- Y -P(O) X 2 ] − ( X Cl, PhO, F; Y NH, O) may be obtained from N-phosphoryl phosphazenes ( I ; X Cl, PhO) and pyrophosphoryl chloride ( II ; X Cl; Y O). All reactions were studied by means of NMR spectroscopy ( 1 H, 19 F, 31 P). The mechanism of the fluoridolysis is discussed.

THE REACTION OF PHOSPHORUS TRICHLORIDE WITH PROPANOLAMINE-1.3

Abstract The reaction of PCl3 with propanolamine-1.3 in the presence of Net3 was studied and found to form two heterocyclic compounds, the 2-chloro-3-dichlorophosphanyl-1.3.2-oxazaphosphorinane and the 2-aminopropoxy-1.3.2-oxazaphosphorinane, which could be isolated and characterized. By low-temperature NMR the formation of the 2-chloro-3-dichlorophosphanyl-1.3.2-oxazaphosphorinane was found to proceed via a diphosphanylated propanolamine-1.3.

On Derivatisation Reactions of N-Phosphanyl-1.3.2-Oxaza- AND -1.3.2-Diazaphosphorinanes

Abstract Derivatisation reactions of N-phosphanylated oxaza- and diaza-phosphorinanes with protic nucleophiles are discussed.

Oxidative fluorination of low-valent phosphorus compounds

Abstract In phosphorus chemistry, carbon tetrachloride has been well established as a mild oxidant of high selectivity. In combination with various nucleophiles it enables the oxidative derivatisation of low-valent phosphorus compounds. With fluorides as nucleophiles different types of PF compounds can be obtained in this manner. Trivalent phosphorus compounds possessing a sufficiently high nucleophilicity react with the reagent combination CCl 4 /Et 3 NHF via fluorophosphonium salts, formed as intermediates, to fluorophosphoranes or hexacoordinated fluorophosphates, (eqn. 1): Phosphanes with alkoxy groups (X  OR′) form preferentially phosphoryl or phosphinyl fluorides, R 2 P(O)F (eqn. 1). Less nucleophilic phosphorus compounds are not oxidized. They undergo fluoridolysis reactions. In the presence of Et 3 N, tetracoordinated compounds with PH functions are converted into the corresponding PF compounds (eqn. 2): R 2 P(Y)H+CCl 4 +F − →R 2 P(Y)F+CHCl 3 +Cl − (ROR′, NR′ 2 , Ar, Alk; YO, S; R′Alk); yields > 80% Even spirocyclic PH compounds undergo this reaction. In this way ( OC 2 H 4 NH) 2 P F, ( OC 6 H 4 NH) 2 P F, N(CH 2 CMe 2 O)P (OMe)F and OC 2 H 4 OP F 4 − can be prepared in good yields.

Fluoridolysis reactions of phosphorus compounds

Abstract The fluoridolysis of various P-Cl-, P-O-, and P-N-compounds such as PCl 5 , R 3−n PCl n , X 3−n Cl n PNPOCl 2 (X = OPh, Ph; n = 0 − 3), Cl 2 P(O)NHP(O)Cl 2 , acyclic and cyclic esters and amides of phosphorous acid with organyl- ammonium fluorides, e. g. Et 3 N·nHF, has been investigated. As a result convenient methods for the preparation of organylfluorophosphanes, R 3−n PF n , [1] several fluorophosphates, [XPF 5 ] − (X = H, RO), and F 2 P(O)NP(O)F 2 − have been developed. Due to the high nucleophilicity and concentration of the fluoride ions, fluorophosphates are formed preferably: [X n PF 6−n ] − : X = F; Cl (n = 4, 5); RO (n = 1−4); H (n = 1); RNH (n = 1). Even an exchange of phosphoryl oxygen by fluoride takes place under certain conditions (e. g. in POCl 3 and (PhO) 2 PClNPOCl 2 ). In the case of N-phosphorylated phosphazenes, X 3−n Cl n PNPOCl 2 with X = OPh and Cl the fluoridolysis effects a cleavage of the PNP-bridge. [(PhO) 2 PFNPF 5 ] − has been detected as intermediate. However, in Ph 3 PPOCl 2 and imidodiphosphoryl compounds the PNP-bridges are stable against fluoride. The factors affecting the course of fluoridolysis reactions and the kind of the reaction products (neutral compounds or hexacoordinated anions) are discussed.

Formation and Stability of Difluoromethylene Phospho-Raiies, R3P=CF2

Abstract Carbonyl compounds react with CBr2F2 in the presence of phosphanes, RP (R = Ph, NR;), and metals (M = Zn, Cd, Pb) forming geminal difluoroolefins (eq. 1)1. R′CHO + CBr2F2 + R3P + M → R′CH=CF2 + MBr2 + R3PO (1) Without any doubt this reaction has to occur via the intermediate formation of difluoromethylene phosphoranes, which then undergo the Wittig reaction with carbonyl compounds (eq. 2). R3P=CF2 + R′CHO → R3PO + R′CH=CF2 (2).

Fluoro-λ-Monophosphazenes and Fluoro-1.3-Diaza-2δ5,4δ5-Diphosphetidines

Abstract 34 new fluoro-λ-monophosphazenes and 37 new fluoro-1.3-diaza-2λ5 4λ5-diphosphetidines have been prepared by applying the STAUDINGER reaction on δ3-phosphorus compounds (eq. (1)).

Reaction of difluorocarbene with covalent halides

Abstract In order to investigate the reaction of the halides MX3 (M = P, As; X = F, Cl, Br, I), PCl5, POCl3, POBr3, RSCl (R = Ph3C, Ph, Et, Cl, SCl), SOCl2, and WF6 with CF2 we used the complex Cd(CF3)2·2 CH3CN as precursor of CF2. In accordance with Krause and Morrison [1] we found that this complex can also react as trifluoromethylation agent depending on the nature of the covalent halide and the reaction conditions. Already at room temperature Cd(CF3)2·2 CH3CN reacts with MX3 (M = As; X = Cl, Br, I; M = P; X = Br, I), PCl5, and S2Cl2 forming difluorohalomethyl compounds, e. g. X2MCF2X, by insertion of CF2. The reaction products are thermically stable substances being rather resistant to hydrolysis in some cases. Only the iodo- derivatives decompose slowly to CI2F2 and to diphosphanes or diarsanes, resp.. In the reaction of CF2 with oxohalides, however, COF2 and the corresponding reduced halides are formed. On the other hand the cadmium complex reacts with RSCl (R = Cl, SCl, Et) as trifluoromethylation agent under substitution of chlorine by a CF3-group forming trifluoromethylsulfanes and CClF3.