Dichlorophosphines

Cowley s group reported in 1987 the condensation of a dichlorophosphine with Collman s reagent to form stable complex 12, for which they obtained an X-ray crystal structure [57]. However, the two nearly equally long P-N bond lengths of 1.777(7) and 1.764(7) indicate that 12 is not an unencumbered species. 

Recently, the group of Lammertsma developed an alternative route, using Collman s reagent and dichlorophosphine 17, to generate Fe(CO)4 complexed phosphinidene 18 in situ [61]. This reactive amino substituted species is trappable at about 0 °C with alkynes and terminal alkenes to give stable phosphirene... 

The same authors also reported the preparation of 1,2-oxaphosphole derivatives from the reaction of alkyl(phenyl)dichlorophosphines with unsaturated ketones (Scheme 4) [33],... 

The most widely applied precursors for the synthesis of monocyclic NHPs are a-diimines which can be converted to the target heterocycles either in a two-step reaction sequence involving two-electron reduction of the diimine to an enediamide, enediamine, or a-aminoamine and subsequent condensation with PC13 [18-20] or a dichlorophosphine RPC12 [21], or via direct base-promoted reaction with PC13 [20, 22], The latter reaction involves addition of a P-Cl bond to each imine moiety followed by base-promoted elimination of hydrogen chloride leading to 2,4-dichloro-... 

Benzannulated NHPs are straightforwardly accessible from AUV-disubsti luted o-phenylenediamines either via base-induced condensation with substituted dichlorophosphines [25] or PC13 [26], or via transamination with tris(dialkylamino) phosphines [13, 14, 27], respectively. An analogous NH-substituted derivative was obtained in low yield via transamination of o-phcnylcncdiaminc with ethoxy-bis(diethylamino)phosphine [28], and condensation of o-phenylenediamine with excess tris(diethylamino)phosphine furnished a l,3-bis(phosphino)-substituted heterocycle [29], Intermediates with one or two NH functions were detectable by spectroscopy but could not be isolated in pure form under these conditions. However, 2-chloro-benzo-l,3,2-diazaphospholene and the corresponding 1-phenyl derivative were prepared in acceptable yield via condensation of PC13 with o-phenylenediamine under microwave irradiation [30], or with A-phenyl-o-phenylenediamine under reflux [27], respectively, in the absence of additional base. The formation of tetrameric benzo-NHPs during transamination of A-alkyl-o-phenylenediamines with P(NMe2)3 has already been mentioned (cf. the section entitled 1,3,2-Diazaphospholes and 1,3,2-Diazaphospholides ). 

Neutral 2,3-dihydro-l,3,2-diazaphosphinines are straightforwardly accessible from condensation of 4-amino-1-azabutadienes with appropriately substituted dichlorophosphines or PC13 (Scheme 16). The reactions are generally carried out in benzene in the presence of triethylamine as acid scavenger, and the products are isolated in excellent yields of 86-96% [86, 87],... 

If trivalent phosphoms compounds are to be treated as electron-deficient species, then reactions of oxadiazoles with some Lewis acids should be reported here. 2-Phenyl-l,3,4-oxadiazole reacting with phosphoms trichloride in pyridine solution in the presence of triethylamine at low temperature furnished the respective dichlorophosphine and chlorophosphine, which were trapped by dimethylamine to give the corresponding amides. 2-Phenyl-l,3,4-oxadiazole also interacts over 24 h with the less reactive chlorodiphenylphosphine and dichlorophenylphosphine at room temperature to give phosphines (Scheme 14) <1999CHE1117>. These reactions of oxadiazoles resemble the behavior of 1-alkylimidazoles toward trivalent phosphorus derivatives. 

Preparation of (l-aminopropyl)phenylphosphinic acid — Reaction of a carbonyl compound with benzyl carbamate and a dichlorophosphine... 

Oleksyszyn, J., Tyka, R., and Mastalerz, R, Direct synthesis of 1-aminoalka-nephosphonic and 1-aminoalkanephosphinic acids from phosphorus trichloride or dichlorophosphines, Synthesis, 479, 1978. 

The iodo-phosphine (50) decomposes at temperatures above —50 °C to give the phosphorane (51).42 Phosphorus trichloride is oxidized by the sulphenyl chloride (52).48 Aryl- and alkyl-dichlorophosphines have been converted into the phosphor-... 

The addition reaction of phosphorus pentachloride to styrene and its derivatives provides a convenient route to styrylphosphonic acids and their derivatives. " The styrene phosphorus pentachloride adduct also can be reduced with phosphorus to give the corresponding dichlorophosphine. ... 

Working with a dichlorinated disilane or dichlorophosphines as electrophiles, 499 and 500 were prepared in low yields from dichlorinated acetylenes 485 and 494 and using a biphenyl-catalyzed (ca 20%) lithiation (Scheme 139) . 

The PCI2 group of 4-dichlorophosphino-l,2,3-diazaphospholes (86) can be transformed by substitution and oxidation reactions as usual for dichlorophosphines <80CB2278) and it provides access to a diazaphospholyl aryliminophosphine (Scheme 28) (Ar = 2,4,6-Bu 3CeH2) <93BSF726> (For the molecular structure of an intermediate see Table 2). 

Diazadiphospholes (182) (R = Me, Ph) are obtained from the condensation of methylene bis(dichlorophosphine) and a hydrazine (Scheme 56) <85AG127>. l-Phenyl-l,2,3,5-diazadiphosphole is a colorless, air-sensitive liquid. It is not alkylated by methyl iodide or trimethyloxonium tetra-... 

Two examples are reported here based on the reaction of Reformatsky reagents with phosphorus(III) electrophiles. In equations 67 and 68, a dichlorophosphine or a monochlorophosphine is reacted with 2 or 1 equivalents of la in the presence of zinc in refluxing benzene. Quenching of the crude unstable tertiary phosphine with H202 allows one to isolate phosphino oxides 116 and 117 in good yields, generally as stable solid compounds154. 

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