Dimethyl phosphane

Das Phosphinsaure-amid I laBt sich nach Metallierung mit Butyl-lithium mit Chlor-dimethyl-phosphan zum au-Berst luftempfindlichen Dimethyl-phosphinsaure-(dimethylphosphano-methyl-umid)-methylimid (64°/0) umset-zcn"2 ... 

Compound 13a can been obtained via two different routes firstly in the reaction of 11 with dimethyl aluminum chloride where LiCl is eliminated and secondly by the reaction of di(pyridyl) phosphane 12 (Py2PH) with trimethyl aluminum where methane is formed, (Scheme 5). The X-ray structure determination of [Me2AlPy2P] 13a, (Fig. 3) elucidates the aluminum atom to be coordinated by the two nitrogen atoms of the pyridyl rings in addition to the two remaining methyl groups leaving the aluminum four... 

Many chiral phosphorus ligands have shown excellent reactivities and enantio-selectivities in the Rh-catalyzed hydrogenation of itaconic acids or esters. Some successful (>95% ee) hydrogenations of itaconic acid or its dimethyl ester with different chiral phosphorus ligands are listed in Table 26.7. High reactivity is observed with electron-rich phosphane ligands such as BICHEP [7c[. 

Little is known about using a P=S bond as a dipolarophilic unit. Indirect evidence of a 1,3-dipolar cycloaddition in the case of 2,2-dimethyl-1-diazopropane with the short-lived amino(thioxo)phosphane R2N—P=S (R = SrMc3) exists (190). More remarkable is the formation of 1,3,4,2-thiadiazaphosphohne 182 from diazo compound 180 and 0.5 equiv of Lawesson s reagent (179) (Scheme 8.41) (241). This and similar results with nitrones and nitrilimines suggest that the monomeric dithiometaphosphate form of 179 can be trapped in a dipolar cycloaddition across the P=S bond. A spontaneous 1,3-R shift in cycloadduct 181 would then lead to the final product. 

Catalytic enantioselective synthesis of 4,4-dimethyl-l-phenyl-l,2-pentadiene from 4,4-dimethyl-1,2-pentadiene and iodobenzene using 0.4 to 1 mol % of palladium complexes containing chiral phosphane ligands as the catalyst for the enantioselective cross coupling134 is the only example of substoichiometric transition metal catalyzed enantioselective allene synthesis. 

Finally, interaction of /3-enamino-A5-phosphanes (120) with dimethyl acetylenedicarboxylate and the subsequent treatment of intermediate 121 with butyllithium gives the A5-phosphole derivatives 122 [89JCS(P1)2273]. 

The reaction of /3-enamino-A5-phosphanes with dimethyl acetylenedi-carboxylate gives l-aza-4A5-phosphinines (244) [89JCS(P1)2273]. Six-membered ring phosphorus-containing heterocycles were obtained by the reaction of enaminophosphines (245) with ethyl azidoformate (87TL2875). 

Reaction of enol ether 1 a with sodium methoxidc or ethoxide. or 1 b with sodium methoxide, gives ketene acetals, which rearrange in the presence of triethylamine to give esters 3.3 The phosphorus ylide trimethoxy[2,2,2-trilluoro-l-(trifluoromethyl)cthylidene]-A ,-phosphane f(CF3)2C = P(OMc),] rearranges readily to dimethyl f2.2,2-trifluoro-1-mcthyl-l-(trifluoro-mcthyi)ethyl]phosphonate [(CF,)2C(Me)PO(OMe)2] in a similar 1.3-shift.5-0... 

Phosphane Dimethyl-trifluoroinc-thyl- ElOb, 665f. 

Phosphane, Dimethyl- (3.3.3-trifluoro-propyl)- ElOb,. 676 (En + HPR2)... 

Platin Bis-[dimethyl-phcnyl-phosphan]-diethinyl-iodo-trifluoromethyl- XIII/9a. 844 (F,G —1 — L2PtR,)... 

Analoge Verbindungen erhalt man auch bei der Alkylierung von Phosphan-phosphano-imiden und bei der Protonierung von Trimethylphosphan-(dimethyl-methylen-phosphor-anylimid)746 747 z.B. ... 

Dimethyl and methyl phenyl 4,4-dimethyl-2,6-dioxocyclohexylidene tellurium compounds transferred a methyl group to triethylamine, triphenylphosphane, tris[di-methylamino]phosphane, and triphenylarsane. The methyl onium cations were isolated as lelraphenylborates. The alkylidene organo telluronium intermediate was identified by 31P-NMR spectroscopy in the reaction of the ylide with tris[dimethylamino]phosphanc . 

An interesting example of a Lewis acid/base reaction between neutral reactants is the formation of tris(n-butyl)phosphonium-dithiocarboxylate, ( -Bu)3P" — 82 , from tris(n-butyl)phosphane and carbon disulfide in solution. As expected, this equilibrium is strongly shifted in favour of the dipolar zwitterion with increasing solvent polarity (diethyl ether dimethyl sulfoxide) [272, 273]. 

Note Reaction of the dimethyl palladium(U) carbene complex with excess methyl iodide leads to decomposition of the compound by reductive elimination of an imidazolium salt that remains pendant on the phosphane anchor [283]. 

Bis(trifluoromethyl)phenyl derivatives with meta substitution of the trifluoromethyl groups can be converted into phosphanes via regioselective lithiation. Thus, Af,fV-dimethyl-3,5-bis(tri-fluoromethyl)aniline (9) can be treated with butyllithium/W,Af,Af. .V -tctramcthylethylene-diamine or with methyllithium alone to yield isomers 10 or 11, respectively. ... 

Similarly, dimethylphosphane reacts nucleophilically with hexafluoropropene to yield the trans-and m-substitution products in ratios which are dependent on the reaction conditions. Irradiation yields a 70 30 mixture of trans- and c/.v-dimethyl(pentafiuoroprop-l-enyl)phosphanes... 

Dimethyl(pentafluoroprop-l-enyl)phosphane (6) Typical Proccdure ... 

Dimethyl(trifluoromcthyl)phosphane(6) was obtained in 50% yield by reacting trimcthyl-phosphanc with trifluoroiodomethane (1). Tetramethylphosphonium iodide was formed as the byproduct. The reaction proceeds via the quarternary salt 5 which eliminates one of the alkyl groups as the alkyl iodide. 

Dimethyl 2-hydroxy-4-((rifluoromethyl)perfluoropcnt-2-yl phosphane Oxide 3 Typical Procedure ... 

Bis-[dimethyl-phenyl-phosphan]-carbonyl-chloro-iodo-per-fluoralkyl- XIII/9b, 337 frans-Bis-[triphenylphosphan]-carbonyl-polyhalogenphenyl-XIII/9b, 314... 

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