Bis phosphoranes

With alkylamines, the primary reaction products are aminophosphonium salts, [Ph3PNHR]+Br , which need to be dehydrobrominated with ammonia or sodium amide. In a similar marmer, dichlorotriphenylphosphorane reacts with hydrazine dihydrochloride, at 180-220 °C, to form a bis(phosphorane)diimine after treatment with a strong base (hquid ammonia or potassium teri-butoxide), equation (3). ... 

Bis phosphoranes have been prepared (6.540) and the molecular dimensions of many phospho-ranes have now been measured, for example, (6.541). 

Reaction (7.283) can be used to obtain a tetra azaphosphorane which will condense with its fluoro derivative to give a bis phosphorane with a P-P bond [10]. 

Useful bi -phosphoranes can be obtained from a, >-dinitriles by an unusual sequence, involving reduction followed by coupling with a phosphorane (Scheme 23) a subsequent Wittig reaction with a dialdehyde leads to isomeric mixtures of cyclic tetraenes in good yield. ... 

Bis(tnfluoromethyl -substituted phosphoranes are obtained on reaction of bis(tnfluoromethyl)-substituted heterodienes and P(ni) species [74J, 742 143] In the case of sulfur- and selemum-contaimng phosphoranes, the corresponding heterodienes are generated in situ from heterocyclic precursors [137] (equation 32)... 

A. Preparation.—Halogen displacement reactions have been used to prepare a number of new aminofluorophosphines. Aminodifluorophos-phine (1) has been prepared for the first time, from either bromodifluoro-phosphine or chlorodifluorophosphine, and ammonia. Studies of its n.m.r. spectrum have been made (see Chapter 11). The related NN-difluoroaminodifluorophosphine (2) has been prepared, from difluoroiodo-phosphine, and found to be explosive. Two syntheses of A-alkyl-amino-difluorophosphines have been reported, one of which was complicated by the subsequent formation of the phosphorane (3) and the bis-(A-alkylamino)fluorophosphine (4). 

A number of preparations of mixed halogenophosphoranes from tervalent phosphorus-fluorine compounds have been reported. For example, acyclic and cyclic fluorine compounds have been converted to phosphoranes, such as (36) and (37), by treatment with chlorine. Similar reactions leading to AA-dialkylaminodichlorodifluorophosphoranes (38) have been described and the stability of (38) to exchange processes commented upon. iVA-Dialkylaminotetraiodophosphoranes (39) have been prepared from AA-dialkylaminodichlorophosphines and lithium iodide, although no detailed physical evidence for the structure of these unusual compounds has yet been reported. The preparation of bis-(A-alkylamino)difluorophosphoranes (4) has been described above (see Section lA). 

The first phosphorane (74) with a a"phosphorus-silicon bond has been prepared (albeit in low, 20%,yield) by the reaction of (72) with bis(trimethylsilyl)magnesium (73)99. It has an unusually high phosphorus chemical shift but no 2L ray data are, as yet, available. 

Treatment of a seleno-subsitituted phosphorane 219 containing a diazaphosphetidinone ring with bis(2-chloro-ethyl)amine hydrochloride and triethylamine gave the spirophosphorane 220 in 21% yield (Equation 43) C1995ZFA2001, 1997ZFA1325>. 

A further example of the diazaphosphole synthesis by [3 + 2] cycloaddition is given by the reaction of a phosphoranediyl diazomethane (26) (R = NPr j) with P-chloro-bis(trimethylsilyl)-phosphaethene. The adduct loses trimethylchlorosilane and yields a 3-phosphoranediyl-l,2,4-diazaphosphole (or 3-phosphonio-l,2,4-diazaphospholide) (27). The analogous addition to the trimethylsilyl substituted P-chloro-bis(methylene)phosphorane (28) yields a 4-methylene derivative (29) of this diazaphosphole (molecular structure in Table 1). It provides the only fully characterized example of this type up to 1995. Methyl triflate methylates the compound at N-1 and gives a phosphonio methylene diazaphosphole cation (30). 

Eine neuere Methode arbeitet mit Bis-[2,2,2-trifluor-ethoxy]-triphenyl-phosphoran als Reagenz (aus Dibrom-triphenylphosphoran und Natrium-2,2,2-trifluor-ethanolat in Ether bei 0°) und ergibt gute Ausbeuten an sekundaren Aminen3 ... 

Die Reaktion von 1,2-Diamino-benzol mit Bis-[2,2,2-trifluor-l-trifluormethyl-ethoxy]-tri-phenyl-phosphoran fuhrt zur N-Monosubstitution unter Bildung von 2-Amino-l-(2,2,2-tr fluor-l-trifluormethyl-ethylamino)-benzol (62%)3 ... 

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