Diphenylphosphanes

A similar transformation of (l-methoxy-2-propenyl)diphenylphosphane oxide leads to (fyS-mcthoxy-l, 3-dienes61. 

A powerful variation of the iron acetyl enolate aldol reaction utilizes the cnolate of complex 8 which bears a (pentafluorophenyl)diphenylphosphane ligand in place of the more usual triphenylphosphane47. The enolate species 9. prepared by treatment of 8 with lithium diiso-propylamide, reacts at — 78 °C with benzaldehyde to produce the aldol adduct 10 with a d.r. of 98.5 1.5. 

As shown in Scheme 18, the reaction of 3-azido-2,3-dideoxynucleoside 36 with polystyryl diphenylphosphane resin (37) affords iminophosphorane 38, which gives amine 39 after hydrolysis. Dioxane or pyridine is used as a solvent, and the purity of the products obtained is identical with those obtained by the normal method (94S789). 

Diphenyl-2-mercaptoacetate ligand, 40 29 Diphenylphosphane, reaction with hexa-... 

MaBige Ausbeuten an optisch aktiven, primaren Aminen mit ee-Werten bis zu 36% erhalt man in einer Dreistufen-Reaktion aus Ketoximen durch Reaktion mit Chlor-diphenyl-phosphan/Base und Reduktion des so gebildeten Alkylidenamino-diphenylphosphans mit Lithium-alanat in Gegenwart von ( —J-Chinin1. 

It has recently been demonstrated that a stereoselective synthesis of dipeptides by hydrogenation of the corresponding monodehydropeptides (N-protected free acids or methyl esters) is possible. In this reaction, chiral catalysts, for example BPPM (13), in the form of a Wilkinson complex have been used. These are superior to the corresponding DIOP complexes (DIOP = P,P -[2,2-dimethyl-l,3-dioxolane-4,5-bis(methylene)]bis(diphenylphosphane). A d.s. value of 90—99% was generally obtained 49 ... 

Ligands with trimethylammonium groups can be prepared by the regio-selective addition of diphenylphosphane to conjugated alkenes with good yields. For example, the alkene CH2=CHC(0)0CH2CH2NMe3l , an acrylic ester, has been used (45). The authors did not report the water solubility. 

Sugar derivatives of phosphanes can be made by reaction of ethylene glycol derivatives with sugar diacetonides to form monoallyl ethers, which can be brominated at the double bond. These compounds react with phenyl-and diphenylphosphanes to yield ligands with a sugar function in the side chain (57). Phosphinated glucopyranosides were prepared by Oehme and... 

Pentafluorophenyl)diphenylphosphane and sodium methoxide in methanol yield diphenyl(tet-rafluoro-4-methoxyphenyl)phosphane (38).106... 

Faure et al92 reported the first enzymatic resolution of phosphane-borane complex. Thus, the borane adduct of (2-hydroxypropyl)diphenylphosphane 107 was resolved using the lipase CAL-B and vinyl acetate as acyl donor in organic solvent. The remaining unreacted substrate (.S )-107 was recovered with 91 % ee. 

Action of tetrachloromethane on trimethylsilyl-substituted methyl-diphenylphosphanes causes quantitative chloroform elimination with formation of trimethylsilylated (TMS) methylenechloro-diphenylphosphoranes. Heating the bistrimethylsilyl substituted... 

The discovery by the recent Nobel-laureate, Ryoji Noyori, of asymmetric hydrogenation of simple ketones to alcohols catalyzed by raras-RuCl2[(S)-binap][(S,S)-dpen] (binap = [l,l -binaphthalene-2,2/-diyl-bis(diphenylphosphane)] dpen = diphenylethylenediamine) is remarkable in several respects (91). The reaction is quantitative within hours, gives enantiomeric excesses (ee) up to 99%, shows high chemoselecti-vity for carbonyl over olefin reduction, and the substrate-to-catalyst ratio is >100,000. Moreover, the non-classical metal-ligand bifunctional catalytic cycle is mechanistically novel and involves heterolytic... 

A brominated polystyrene is reacted with sodium diphenylphosphan to form the polymeric Wittig reagent. Reaction with a halide and a base form the ylid which reacts with the carbonyl compound to the olefin. Wittig olefination can be made stereoselective (33). The formation of cis-olefins is accomplished in salt-free solu-... 

Mit Tetrachlor- 1,4-benzochinon reagiert Diphenylphosphan in 46% Ausbeute zu Diphe-nyl-(4-hydroxy-2,3,5,6-tetrachlor-phenyl)-phosphanoxid5 zusatzlich wird Diphenyl-phosphinsaure-phenylester gebildet. Aus Diphenylphosphan und 4-Dimethylamino-benzaldehyd bildet sich in Acetonitril auf noch ungeklarte Weise Bis-[diphenylphos-p/zmy/]-(4-dimethylamino-phenyl)-methan5a. 

Benzoyl-diphenyl-phosphanoxid, das aus Benzoesaureanhydrid und Diphenylphosphan-oxid entsteht, ist extrem hydrolyseempfindlich und addiert Spuren von Wasser zu Diphe-nylphosphinsaure-a-diphenylphosphinyl-benzylester und bildet bereits bei 85° ein Dime-... 

Diphenylphosphan laBt sich mit Phenylselenobromid in Gegenwart von Wasser in 80%i-ger Ausbeute in Diphenyl-selenophosphinsdure-Se-phenylester iiberfuhren10Sdas auch durch Spaltung von Tetraphenyl-diphosphan-bis-oxid mit Phenylselenobromid entsteht (94%)10S1 ... 

The primary addition product from HFA and diphenylphosphane (32b) has been unambiguously characterized by several groups (97, 755). It is easily oxidized by atmospheric oxygen and dinitrogen tetroxide (97, 755) to form phosphonous acid ester 33b via phosphane oxide 36 (755), which can also be synthesized from HFA and diphenylphosphane oxide. Kinetics of the base-catalyzed rearrangement have been studied (754). Further action of HFA on 32b yields difluorophosphorane 37 (755). A dipolar intermediate with tetra-coordinated phosphorus has been postulated by Stockel (260) in the formation of 33b and 33c (R = c-CgHu). 

A second access to these four-membered ring systems is the action of alkyl halides on the adduct of diphenylphosphane with HFA (32b) [Eq. (53)] (96). 

Rychnovsky and his group have recently developed new synthetic methods that lead to the total syntheses of the polyene macrolides roxaticin [2], roflamycoin [3], and filipin III [4]. The polyol chains of all three natural products were constructed by iterative, stereoselective alkylation of lithiated cyanohydrin acetonides and subsequent reductive decyanation, illustrated here by the synthesis of the polyol framework of filipin III (1) (Scheme I). The bifunctional cyanohydrin acetonide 2, prepared by ruthenium/BINAP catalyzed enantioselective hydrogenation of the corresponding ) -keto ester (BINAP = [ 1,1 -binaphthyl]-2,2 -diylbis(diphenylphosphane)), is deprotonated with LiNEt2 and alkylated with 2-benzyloxy-l-iodoethane. The alkylation product 3 is converted by a Finkelstein reaction into the iodide 4, which is used to alkylate a second... 

Diphenylphosphanyl radicals, Ph2P , generated from diphenylphosphane in the presence of a radical initiator were used to cyclize the alkynyl-substituted carbohydrate derivative 195 in a radical addition/S-exo cyclization sequence to give the bicyclic deoxysugar derivative 196 (Scheme 2.36). Ph2p have also been used as promoters for the cyclization of alkynyl p-lactam 181 for a highly efficient, diaster-eoselective synthesis of bicyclic p-lactams (see Scheme 2.33). ... 

A radical diphosphanylation of alkynes using tetraorganodiphosphanes as precursors for phosphanyl radicals has been applied to the synthesis of a doubly phosphinated diene 200 (Scheme 2.37)7 Tetraphenyldiphosphane was generated in situ from diphenylphosphane with an excess of chlorodiphenylphosphane in the presence of triethylamine. Addition of the phosphanyl radical to one C = C triple bond in the dialkyne 199 leads to vinyl radical 201, which undergoes a 5-exo cyclization (out of a Z-configured vinyl radical to minimize sterical hindrance in the cyclization) to give vinyl radical intermediate 202. The latter is trapped by a second phosphine moiety in a radical substitution step. The radical cyclization product is ultimately isolated as bis-phosphane sulfide 200 after treatment of the intermediate phosphane 203 with sulfur. 

Reaction of perfluorooctanonitrile (5) with diphenylphosphane gives one of two products, depending on the reaction conditions a primary adduct 6 and the reduced adduct 7 formation of the latter is prevented by the presence of water. - ... 

Thus. 1,2-dichlorohexafIuorocycIopentene (1) reacts smoothly with diphenylphosphane to give only the monosubstituted derivative in good yield. In the case of the more nucleophilic dicyclohexylphosphanc, the formation of the mono- and disubstituted derivatives 3 and 4, respectively, is observed.22... 

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