Phosphane

The reactivity of fluoro(organyl)phosphanes depends on the nucleophilicity of phosphorus For mstance the phosphanes may add to the carbonyl carbon to form phosphiniio phosphoranes (equation 36) or may react with acid fluondes to form acyldifhiorophosphoranes [37] (equation 37)... 

Nucleophiles like alcohols [2, S], hydrogen sulfide [2], thiols [2,10], ammonia, amines, hydrazines, hydroxylamines [2 11, 12, 13, 14, 75], azides [2], other pseudohalides [2], phosphonates [2,16,17,18,19, 20], and phosphanes [2,19] add rapidly across the CO or CN double bond to yield stable adducts The phosphonate adduets undergo a subsequent aleohol—lester rearrangement [19, 20] (equation 2)... 

Only a few reactions of benzodithiadiazines have been investigated. In common with dithiatriazines 12.8, the anti-aromatic system 12.12 (R = H) undergoes a reversible 5,5 -cycloaddition with norbornadiene. The reaction of 12.12 (R = F) with triphenylphosphine results in a ring contraction to give the imino 2 -phosphane 12.13. ... 

Tlie desulfurization of thiono compounds is another frequently used synthetic approach for the formation of double bonds via carbenoid intermediates. By this methodology, some indigoid 1,3,5,7-tetraazafulvalenes 88 and 90 were synthesized (83BSB781 90JPR949).Tliis dimerization starting from 2,4,5-tris(dimethylamino)imidazolium chloride via the appropriate thione 87 has been realized in the presence of phosphanes or phosphites to... 

Attempts to prepare 2-butoxy-3//-azepines by heating nitro compounds with tris(di-ethylamino)phosphane in /m-butyl alcohol failed, as diethylamine, liberated by alcoholysis of the aminophosphane, reacts in preference with the alcohol (vide supra) to give the Ar,/V-di-ethyl-3//-azepin-2-amine in good yield.176 However, the deoxygenation of nitroarenes with tributylphosphane in the presence of primary and secondary alcohols furnishes 2-alkoxy-3//-azepines 98 in practicable yields.79... 

Two intramolecular aza-Wittig reactions leading to 1,3-benzoxazepines have been described. In the first,19 ethyl (Z)-3-(2-acyloxyphenyl)-2-azidoprop-2-enoates 1 are treated with triphenyl-phosphane under argon at 20°C for 3-4 hours when 2-substituted ethyl 1,3-benzoxazepine-4-carboxylates 2 are obtained in 85-90% yield. 

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... 

Similarly, reaction of the bis(imino-/.5-phosphane) 4 with aroyl chlorides gives 1,3-benzodiazepines, which, however, were assigned the 1//-structures 5. < 3a-b... 

The bis(imino-A5-phosphane) 4 (0.508 g, 0.7 mmol) in CH2C12 (25 mL) was slowly treated with an aroyl chloride (0.7 mmol) and Et3N (0.07 g, 0.7 mmol) and the mixture was stirred at 20 C for 7 h. The solvent was removed in vacuo, benzene (15mL) was added, the precipitated Et3N HC1 was filtered off and the filtrate was evaporated under reduced pressure. Chromatography of the residue (silica gel, EtOAc/hexane 1 2) gave the red product, which was recrystallized (EtOH). 

The bis(imino-l5-phosphane) 1 reacts with a molar equivalent of an isocyanate in toluene at 20 C for 16 hours to give pyrazolo[3,4-<7]-l,3-diazepines 2. No further details were reported.167"b... 

The tricyclic 1,3-diazepines 3 are formed by the action of two molar equivalents of aromatic isocyanates on the bis(imino-A5-phosphane) 1 in toluene at 20 C for 16 hours in a tandem aza-Wittig [2 t 2]-cycloaddition reaction . No further details were reported.167... 

Azido-l, 4-benzodiazepin-2-ones 43 arc obtained from 1,4-benzodiazepin-2-ones by treatment with potassium bis(trimethylsilyl)amide, followed by 2,4,6-triisopropylbenzencsulfonyl azide. The azides are reduced to the corresponding amino compounds 44 by the action of triphenyl-phosphane in aqueous tetrahydrofuran. No further details were reported.429... 

N,AP-Diacylbenzene-1,2-diamines 1 are converted into 3,1,5-benzoxadiazepines 2 by the action of dibromotriphenyl-A5-phosphane.321... 

Alkylation of the anion 2 with iodomethane or other haloalkanes provides alkyldicarbonyl(t/5-cyclopentadienyl)iron complexes such as 53,0 (see also Houben-Weyl, Vol. 13/9a, p 209). Migratory insertion of carbon monoxide occurs on treatment with phosphanes or phosphites9 -11 (see also Houben-Weyl, Vol. d3/9a, p257) to provide chiral iron-acyl complexes such as 6. This is the most commonly used preparation of racemic chiral iron-acyl complexes. 

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. 

Incorporation of a chiral phosphane allowed resolution of the complex 6 which was obtained in enantiomerically pure form. Reaction of 6 with 2,2-dimethylpropanal provided the adduct 7 as the sole observable aldol product13. Oxidation of the metal center of 7 with ferric chloride induced decomplexation via reductive elimination, to provide the enantiomerically pure cy-clobutanone 8. 

The versatility of tertiary phosphane ligands in coordination and organometallic chemistry. R. Mason and D. W. Meek, Angew. Chem., Int. Ed. Engl., 1978,17,183-194 (138). 

Wahrend 2-Halogen-1-oxo-l-phenyl-alkane mit Triphenyl-phosphan zu (2-Oxo-2-phenyl-athyl)-triphenyl-phosphoniumhalogeniden reagieren, werden sek. und tert.-x -Brom-ketone in siedendem Benzol-Methanol-Gemisch (auch mit Zusatz von Salzsaure) (bestes Verhaltnis 8,4 1) zum Keton enthalogeniert1 ... 

Trichlor-l-diathyIamino-athyIcn1 Unter Stickstoff gibt man 40,5 g (0,2 Mol) Tributyl-phosphan bei 25° zu 43,7 g (0,2 Mol) N,N-Diathyl-2,2,2-trichlor-acetamid. Die Temp, steigt auf 50°. Die Zugabe ist nach 30 Min. bei Kiihlen mit cincm Wasscrbad beendet. Man erhitzt weitere 4 Stdn. auf 50-55° und destilliert anschlie-Bend durch eine 15 x 150-mm-Vigreux-Kolonne Ausbeute 33,4 g (82% d.Th.) Kp7 63-64°. 

Oxirane lassen sich durch Methyl-diphenyl-phosphan unter Konfigurationsum-kehr (98%ige Stereospezifitat) zu Alkenen reduzieren (Phosphor-Betain-Methode)2 ... 

Analog verhalten sich Thiirane gegeniiber Triphenyl-phosphan ... 

Carbonyl-Verbindungen werden durch Triorgano-phosphane unter Dimerisierung zu Diolen reduziert (Bd. VI/la/2, 1498) Chinole und deren Derivate gehen in Phenole iiber (s. Bd. VII/3b, S.741). 

Die Reduktion von Hydroperoxiden mit Trialkyl- und Triphenyl-phosphan fiihrt in z. T. hohen Ausbeuten zu Alkoholen4,5 ... 

Aus a -Hydroperoxy-dialkyldiazenen bilden sich mit Triphenyl-phosphan in z. Tl. guten Ausbeuten trans- a -Hydroxy-dialkyldiazene1 ... 

Ozonide werden durch Triphenyl-phosphan reduziert. So erhalt man z.B. aus Stil-ben-ozonid Benzaldehyd bzw. aus Triphenyl-athen-ozonid Benzophenon und Benzalde-hyd5. Diese Reduktion kann zur quantitativen Bestimmung der Ozonide durch Titration des Reduktionsprodukts herangezogen werden6. 

Zur Reduktion von Benzolsulfochloridbzw. -bromid mit Triathyl- Oder Triphenyl-phosphan zu Benzolsulfin-sdure, Thiophenol und Diphenyl-disulfan s.Lit.7. 

Sulfoxide lassen sich durch Triphenyl-phosphan mit z. Tl. sehr guten Ausbeuten zu S u I -fanen reduzieren1 ... 

Sulfane aus Disulfanen mit Triphenyl-phosphan allgemeine Arbeitsvorschrift4 10 mMol des Phosphans und 10 mMol des Disulfans in 30 ml Benzol werden 8 Stdn. unter RiickfluB erhitzt. Man laBt abkiihlen und zieht das Benzol i. Vak. ab. Die entstandenen Kristalle werden gepulvert und 15 Min. mit 200 ml dcstilliertem Wasser ge-kocht. Man filtriert heiB und kristallisiert die aus dem Filtrat ausfallenden Kristalle in verd. Athanol um. 

Die Reduktion von 1-Chlor-l-nitro-2 bzw. 1-Chlor-l-nitroso-cycloalkanen3 durch Tri-phenyl-phosphan kann zur Herstellung von Lactamen verwendet werden z.B. ... 

Nitroso- 1-aryl-benzole lassen sich durch Triphenyl-phosphan oder Triathyl-phosphit unter Cyclisierung zu Heterocyclen reduzieren (s.Bd. X/l, S. 1076). 

Dinitroso-benzol wird durch Tributyl- oder Triphenyl-phosphan zu Benzofurazan, 1,2-Dinitroso-naphthalin (2 Stdn. Kochen unter N2) zu Naphtho-[l,2-c]-furazan (65% d.Th. F 77-78°) und 4,5-Dinitroso-3,6-diphenyl-pyridazin zu4,7-Diphenyl- furazano-[.3,4-d]-pyridaZin) (36% d.Th. F 193-195°) reduziert4 ... 

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