Triphenylphosphan

Benzoxepin (4) was obtained in 55% yield by the reaction of phthalaldehyde with the bis-ylide generated from the bis(triphenylphosphonium) salt prepared from bis(bromomethyl) ether and triphenylphosphane.93,94... 

Numerous reactions have been described in which the oxygen of the oxepin system is removed to give benzene derivatives. The formation of the aromatic products can be rationalized by an arene oxide as intermediate. A suitable reagent for the elimination of an oxygen atom from this heterocycle is triphenylphosphane, e.g. formation of l,24 2a,12 and 2b.1,9... 

Also, the different stabilities of 3-benzothiepins are reflected by the conditions of sulfur extrusion dibenzo[A,d]thiepin (13) is desulfurized by triphenylphosphane in refluxing xylene, while ethyl 3-benzothiepin-2-carboxylate (14) (see Section 2.1.3.4.) already loses sulfur at room temperature with a half-life of 54 minutes.5... 

Bulky substituents make it possible to prepare a stable 8n-electron thiepin. For that purpose, the methoxycarbonyl groups of furanothiepin 6 (R = C02Me) are converted with methylmagne-sium bromide to the corresponding diol (R = CMe2OH) which reacts spontaneously with N-phenylmaleimide to give the thermally stable endo-thiepin 8.67 Quantitative desulfurization is achieved in the presence of triphenylphosphane. 

Deoxygenation of benzyl nitrosoformate, generated by retro-Diels-Alder reaction of its [4 + 2] cycloadduct 27 with 9,10-dimethylanthracene, with triphenylphosphane in anhydrous benzene yields the unstable benzyl 1//-azepine-1-carboxylate (28).143... 

Treatment of dibcnz[e,/J[1,2]oxazepine-l 1-carbonitrile or 1 l-chlorodibenz[c,/][l,2]oxazepine with triphenylphosphane in acetonitrile at room temperature yields the acridines 5 quantitatively.7... 

The reaction of 5-chloro-l,4-benzoxazepine (4), whose preparation is described below, with tributyltin hydride catalyzed by tetrakis(triphenylphosphane)palladium(0) gives 1,4-benzox-azepine (5).32... 

Di-/m-butyl-5-methoxy-l,4-thiazepine when heated with triphenylphosphane in benzene gives 4,5-di-f( >7-butyl-2-methoxypyridine with the extrusion of sulfur.48... 

The 3-[2-(acylamino)phenyl]-2-azidoprop-2-enoates 1 undergo a Staudinger reaction on treatment with triphenylphosphane at 20 C to give the stable imino-/.5-phosphanes 2 in nearly quantitative yields. The latter cyclize to 3/7-1,3-benzodiazepines 3 (40-50%) when heated in refluxing xylene for 15 hours. No further details were reported.19... 

A degassed suspension of lhe halo compound 14 and an alkyne (1.2 equiv) in Et3N (0.1-0.2 mol) was stirred in the presence of dichlorobis(triphenylphosphane)palladium(II) (0.02 equiv) and coppcr(I) iodide (0.04 equiv) at 20 C for 20 h. EtOAc was added and the mixture was washed with H20 and brine the organic phase was dried (MgSOi) and evaporated to yield the product. 

An intramolecular aza-Wittig reaction of the imino-A5-phosphancs 4, prepared by the action of triphenylphosphane on the corresponding azido compounds, affords l//-l,2,4-benzo-triazepines 5.346 The reactions were carried out by heating compounds 4 in acetonitrile or 2-hydroxyethyl methyl ether for the time indicated. No further details were reported. 

Similarly, benzopentathiepin is degraded to 2 when treated with ethylmagnesium bromide in the presence of triphenylphosphane.405... 

The cobalt corroles are as expected isolated as neutral cobalt(III) complexes with an additional neutral axial ligand, which in most cases is triphenylphosphane or pyridine. 

Schemes based on the acid-catalyzed condensation of a bipyrrole with a dipyrrylmethane are in general unsuccessful for the synthesis of corroles. Thus, the bipyrroles 1 fail to give corroles when reacted with the appropriate dipyrrylmethane 2.10,11 However, cobalt(III) corrole 3 can be prepared in moderate yield by a [2 + 2] approach involving bipyrrole T and dipyrrylmethane 2 bearing formyl groups and carboxylic groups, respectively, and heating initial condensation products, presumably norbilenes, with cobalt(II) acetate and triphenylphosphane in methanol.12...

Acctyl(carbonylXi 5-cyclopentadienyl)(triphenylphosphane)irons ( + )-(.V)-4 and (-H MI14 l5 ... 

Another route to enantiomcrically pure iron-acyl complexes depends on a resolution of diastereomeric substituted iron-alkyl complexes16,17. Reaction of enantiomerically pure chloromethyl menthyl ether (6) with the anion of 5 provides the menthyloxymethyl complex 7. Photolysis of 7 in the presence of triphenylphosphane induces migratory insertion of carbon monoxide to provide a racemic mixture of the diastereomeric phosphane-substituted menthyloxymethyl complexes (-)-(/ )-8 and ( + )-( )-8 which are resolved by fractional crystallization. Treatment of either diastereomer (—)-(/J)-8 or ( I )-(.V)-8 with gaseous hydrogen chloride (see also Houben-Weyl, Vol 13/9a, p437) affords the enantiomeric chloromethyl complexes (-)-(R)-9 or (+ )-(S)-9 without epimerization of the iron center. 

Carbonyl(i s-cyclopentadienyl)methyl(triphenylphosphane)iron (11, R — H) Typical Procedure16 ... 

Alkyl(carbony])(75-cyclopentadienyl)(triphenylphosphane)irons 11 (R = alkyl) General Procedure16 ... 

Carbonyl(q5-cyclopentadienyl)[( )-l-oxo-2-pentenylj(triphenylphosphane)iron ( )-3, R1 = C2II, Typical Procedure23 ... 

Table 3. Iron-Acyl Complexes 11 from CarbonyUr/ -acyclopentadienylHl-oxo -ftriinethylsilyllethyl] (triphenylphosphane)iron (8) by the Aldol Reaction with Aldehydes...

Carbonyl(f5-cyclopentadienyl)(l-oxo-2-butenyl)(triphenylphosphane)iron (II, R = CH ) Typical Procedure25,24 ... 

Carbonyl(i/5-cyclopentadienyl)(3-hydroxy-4-methyl-l-oxopentyl)(triphenylphosphane)irons (2, 3, R = t -Pr) Typical Procedure26 ... 

This high diastereoselectivity contrasts dramatically with the nearly nonexistent selectivity of the lithium enolate of the corresponding triphenylphosphane complexes (vide supra). The diastereomer preferentially obtained from the fluorophenyl lithium enolate 9 corresponds to the major product produced by reaction of the aluminum enolate 1 b derived from the parent triphenylphosphane complex. 

Zinn(lI)-chlorid 488 Diphenyl- 32. 465f.. 506, 534 aus Diphenylsulfoxid und Molybdan(V)-chlorid 524 Triphenylphosphan 572 Zinn(II)-ch]orid 489 Dipropyl- 465 f -Hydroxy- 434 ff. oi-Hydroxy- 434ff. 

Korth K, Schorm A, Sundermeyer J, Hermann H, Boche G (2000) lodotrimethylsUyl-methylene-triphenylphosphane. In Weis J (ed) OrganosUicon chemistry IV from molecules to materials. WUey-VCH, p 238 Gilheany DG (1994) Chem Rev 94 1339... 

Moreover, a twofold SN -type domino reaction was reported by Krische and coworkers for the synthesis of y-butenolides 2-229 (Scheme 2.53) [128]. Treatment of Morita-Baylis-Hillman acetates 2-226 with trimethylsilyloxyfuran (2-227) in the presence of triphenylphosphane in THF at 0 °C led to 2-229 in yields of up to 94% and diastereoselectivities of >95 5. 

To date, only double Heck reactions have been described, but triple Heck reactions are also possible [39]. Reaction of the alkynyl aryl iodide 6/1-55 with norbor-nene in the presence of Pd(OAc)2, triphenylphosphane and triethylamine as base led to the cyclopropanated norbornene derivate 6/1-59 as a single diastereomer in 40% yield (Scheme 6/1.13). It can be assumed that the alkenyl Pd-species 6/1-56 is first formed stereoselectively, and this undergoes a Heck reaction with norbornene... 

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