Phosphoranes reactions with

Spirobicyclic phosphoranes, reaction with hex-afluoroacetone, 30 236 Spirobicyclotriphosphazene, 21 110 Spirocyelic phosphoranes, 30 245 square-planar structure, 30 248 synthesis, 30 252... 

The first synthesis of 289 and 290 started from the base-catalyzed addition of a sugar containing an isolated hydroxyl group to 2,7-dimethyl-3,5-octa-dyine-2,7-diol (286). Two enynyl ethers (287 and 288) were formed and separated, the partial hydrogenation over a Lindlar catalyst affording dienyl ethers 289 and 290. Alternatively, both ethers were prepared by a Wittig reaction from chloromethyl ether (291) a phosphonium salt (292) was prepared and converted into a phosphorane. Reaction with acrylaldehyde gave a mixture of 289 and 290. 

The submitters have shown that these reactions proceed by dehydro-chlorination of the acid chloride to the ketene, which is then trapped by reaction with the phosphorane. The resulting betaine decomposes to the allenic ester via an oxaphosphetane. In contrast, the reaction of acid chlorides with 2 equivalents of phosphoranes involves initial acylation of the phosphorane followed by proton elimination from the phosphonium salt. ... 

Nonclassical Wittig reaction, olefination by phosphoranes interaction with carboxylic acid derivatives, in transformation of heterocycles 99JCS(P1)3049. 

In the following procedure, use is made of the basic character of epoxides. In the presence of phosphonium salts, ethylene oxide removes hydrogen halide and the alkylidenetriphenylphosphorane is produced. If a suitable carbonyl compound is present in the reaction mixture, its reaction with the in situ generated phosphorane proceeds readily to give the Wittig product. 

Triphenylphosphine, in preparation of dichloromethylenetriphenyl-phosphorane, 46, 33 reaction with N,N-dimethylamino-benzaldehyde to yield /9,0-di-chloro-p-dimethylaminostyrene, 46,33... 

Phenylcyclopent[c]azcpine (33a) and 6,7-fused cyclopentazepines 33b-d are formed in moderate yields in a one-pot, two-stage process involving initial condensation of triphenyl-[(l-phenylvinyl)imino]phosphoranes 32 with 6-(dimethylamino)fulvene-2-carbaldehyde (30), followed by an intramolecular aza-Wittig reaction of the iminophosphorane with the pendant aldehyde function.5 The method fails with the unsubstituted vinylphosphorane 32 (R1 = R2 = H). 

D. Miscellaneous.—Low yields of the spirophosphoranes (34) were obtained on heating the phosphorane (32) with the aziridines (33). Stable phosphoranes have been obtained from phenanthraquinone mono-imine (35) and trialkyl phosphites, and from 2-chlorotropone (36) and ylides. In the latter reaction cyanomethylenetriphenylphosphorane gave instead the betaine (37). 

Few examples of A-(phosphino)phosphazenes, RzP N=PRg, are known, but aminophosphines with P-perfluoroalkyl substituents have now been converted into A-phosphinophosphazenes by reaction with phosphoranes in the presence of triethylamine ... 

Acyclic phosphoranes. - A number of difluorotris(perfluoro-alkyl)phosphoranes (7) have been prepared by electrochemical fluor-ination of trialkylphosphine oxides (6) in anhydrous HF17. The phosphoranes are conveniently converted into the perfluoroalkyl-phosphine oxides (8) by reaction with hexamethyldisiloxane and the phosphoranes are regenerated by treatment of (8) with HF. 

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. 

Because in this case an elimination reaction could occur to form an a,/ -unsaturated ester, use of two equivalents of the phosphorane should be avoided.1The (a-acylalk-ylidene)triphenylphosphorane can be subjected to a subsequent Wittig reaction with an aldehyde.[4] [5],[8]... 

Viewed systematically, formation of the olefins 24 on reaction of methyleneoxo-phosphorane 9 with a,P-unsaturated carbonyl compounds is to be classified as an olefination reaction. The similarity to the Wittig reaction is obvious, the differences being just a matter of degree. 

However, other reaction directions via the formation of the phosphorane structure with migration of the methyl anion from one phosphorus atom... 

The formation of the stable betaine system P+—C—O—B is the driving force for this reaction. With 4,6-disubstituted ammonium 1,3,2,5-dioxaborataphosphorinanes (108), there is the possibility of making a choice between two reaction directions. The reaction product formed by the phosphorane transition state, as 1,3,2,5-dioxaborataphosphoniarinane... 

E,Z)-l -Dienes.1 This unit, often present in insect pheromones, can be obtained with high stereoselectivity by reaction of an aldehyde with 1 to provide an (E)-a,p-enal (2), which on reaction with a phosphorane generated with BuLi and HMPT provides (E,Z)-dienes almost exclusively. 

Reaction with a first aldehyde transforms 176 into the vinylphosphonium chloride 177, which for practical reasons is subjected to an anion-exchange process, leading to the phosphonium salt 178. From this, phenyllithium treatment liberates the allenic phosphorane 179, an intermediate that has previously been used to prepare allenes from aldehydes [69], in the present case providing the products 180. The same protocol has also been applied to o-alkynylbenzaldehydes to yield allenes of interest as model compounds for the study of Schmittel and Myers-type cyclization reactions [70]. 

Ring opening of diphenylthiiren 1,1-dioxide5 8 and diphenylcyclopropenone6 occurs on reaction with tertiary phosphines to form the betaines (69) and the keten phosphoranes (70), respectively. Tertiary phosphines react with the thione (71) to form mainly the betaine (72).60... 

Details have appeared39 of the addition of PH-tetraoxyspirophosphoranes to aldehydes and activated ketones. These phosphoranes also add to activated acetylenes,40 e.g. diethyl acetylenedicarboxylate with (50) gives a mixture of cis- and trans-(51). Further addition of (50) to (51) at higher temperatures gives the bisphos-phorane (52). Metallation of the spirophosphorane (53) followed by reaction with... 

Formate esters behave as typical carbonyl compounds in reactions with a number of ylides, eliminating phosphine oxide and forming vinyl ethers, e.g. (33).35 Stabilized phosphoranes are able to condense with the carbonyl group of cyclic thioanhydrides (34).38 Quinoline derivatives, e.g. (35), are obtained from the condensation of dicar-boalkoxy-ylides with isocyanates.37 Benzoyl isothiocyanates and keto-phosphoranes give quantitative yields of (36), which are unreactive in Wittig reactions but can be readily oxidized by selenous acid.38 The products obtained from reactions (Scheme 9) with the triazolinedione (37) depend upon the stability of the ylide used.39... 

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