Diphenyl- phosphine selenide

Structural and Physical Aspects. - The stability of the various conformers of the phosphines oxides (269)- 211) has received theoretical consideration. A new triclinic polymorph of triphenylphosphine sulfide has been structurally characterised, together with a related triclinic polymorph of triphenylphos-phine. Two reports of the solid state crystal structure of the phenolic phosphine oxide (272) have appeared. A crystallographic study has confirmed that the product of electrochemical oxidation of o-diphenylphosphinoben-zenethiol is the disulfide-bridged bis(phosphine oxide) (273). Solid-state structural studies of the dioxides (274), the (i )-(-I-)-isomer of (275), 1-hexynyl(diphenyl)phosphine oxide,tribenzylphosphine oxide, and tris(t-butyl)phosphine selenide," have also been reported. 

In order to prepare transition-metal selenido clusters, different synthetic routes are presently available, such as those involving, as starting materials, diphenyl dis-elenide, phenylselenyl chloride,selenofene, trialkylsilyl selenides, " poly-selenide anions, " and phosphine selenides.Furthermore, small selenido clusters, such as [Fe2(//-Se2)(CO)6] and [Fe3(/i3-Se)2(CO)9], can be conveniently used to prepare larger mono- and bimetallic species, as described in Sec. 1.11.5. 

Reactions of phosphines and phosphites have received some attention but their preparative value is limited. The zwitterion formed from diphenylmethylphosphine and benzyne rearranges to ylide (124) which can be captured by Wittig alkenation, with cyclohexanone, in about 20% yield.159 Some synthetically useful reactions of tellurium and selenium compounds with arynes have been reported. For example, heating diphenyl iodonium carboxylate and bis(p-ethoxyphenyl) ditelluride in dichlorobenzene affords the compound (125).160 The corresponding reactions with diphenyl selenide and diphenyl sulfide... 

Treatment of diphenyl diselenide with tributylphosphine in an alkaline medium generates a benzeneselenolate anion [24], which reacts with various electrophiles, such as halides, epoxides, a, -unsaturated ketones, to generate various selenides [24,25]. The mechanism for the generation of the benzeneselenolate is proposed as shown in Scheme 17 [25]. A selenophosphonium ion and/or a pentavalent phosphorus species are initially formed in the reaction of diphenyl diselenide and tributylphosphine, and then the addition of sodium hydroxide liberates the benzeneselenolate and phosphine oxide. 

Selenolates prepared from diphenyl or dimethyl diselenide by reduction with NaBH4 smoothly transform various benzylic alcohols 24 into the corresponding selenides 25 in the presence of aluminum chloride (Scheme 30 a) [41]. AICI3 is considered to activate the alcohol substrate by coordinating to the oxygen. Similar transformations are possible by the reaction of alcohols with phenyl selenocyanate in the presence of tributyl phosphine [52]. When the selenolate is reacted with aromatic aldehydes or ketones 26 in the presence of AICI3, the corresponding benzylic selenides 27 are obtained in moderate yields (Scheme 30b) [41]. 

A new one-pot method has been developed by Kraszewski for the synthesis of aryl nucleoside phosphate (3a-p) and phosphorothioate (4a-p) diesters. This method, based on H-phosphonate chemistry, employed diphenyl phosphoroch-loridate and a series of phenols. Depending on the substituents present on the phenols, oxidation conditions were optimized to avoid competing hydrolysis. A versatile procedure that permits easy access to H-phosphonoselenoate monoesters (5) has been developed by Stawinski. These monoesters, obtained by selenisation of a phosphinate using triphenylphosphine selenide in combination with trimethylsilyl chloride, reacted with a suitable nucleoside in pyridine/acetonitrile in the presence of diphenyl phosphorochloridate to yield... 

Several sulfenyl group sources are also known [60,61]. Diphenyl selenide was reported [52]. Diphenylphosphorus chloride was used extensively in the synthesis of new phosphines [38,47,51,62]. A chiral version is shown in Eq. (6) [51]. 

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