Phenyl selenocyanate

Diphenyl diselenide has been prepared by disproportionation of phenyl selenocyanate in the presence of potassium hydroxide" or ammonia/ and by air oxidation of benzeneselenol. The preparation of benzeneselenol is described in an earlier volume in this series/ In the present procedure phenylselenomagnesium bromide formed from phenylmagnesium bromide and selenium is oxidized directly to diphenyl diselenide with bromine/ Thus the liberation of the malodorous and toxic hydrogen selenide and benzeneselenol is avoided. Benzeneselenenyl chloride has been prepared by thermal elimination of ethyl chloride from ethyl phenyl selenide di-chloride/ by thermal elimination of chlorine from phenylselenium trichloride," and by chlorinolysis of diphenyl diselenide with either sulfuryl chloride " or chlorine. " ... 

Phenyl selenocyanate Selenocyanic acid, phenyl ester (8, 9) (2179-... 

OH - Br. A primary or secondary alcohol can be converted to the alkyl phenyl selenide by reaction with phenyl selenocyanate and tri-n-butylphosphine (7, 252-253). Reaction with Br2 and triethylamine (7, 34-35) replaces the SeC6H5 group by Br. 

The selenocyano-group may be introduced conveniently into the benzene nucleus by the aid of the diazo-reaction, e.g. diazotised aniline reacts with potassium selenocyanate to yield phenyl selenocyanate ... 

Phenyl selenocyanate, C6H5SeCN, 8, 119-120 9, 34. A simple preparation involves the reaction of C6HsSeCl with (CH3)3SiCN in THF or CH2C12 (96% yield). 

Cyartoselenenylation.2 In the presence of a Lewis acid, particularly SnCl4, phenyl selenocyanate adds to alkenes to form trans-adducts in high yield. Two regioisomers are formed from unsymmetrical alkenes. 

CURTIUS DEGRADATION Diphenylphosphinyl azide. CYANOSELENANYLATION Phenyl selenocyanate. 

Phenyl N-phenylphosphoramidochloridatc, 416 Phenylselenenylation, 219 Phenyl selenocyanate, 33, 416-417 (3-Phcnylselcnoindole, 37, 38 N-Phenylselenophthalimide, 417-418 3-Phenylseleno sulfones, 407, 408 (3-(Phenylseleno)vinyl sulfones, 408 Phenyl sulfates, 410 Phenylsulfinylacetonitrile, 418-419 4-(Phenylsulfmyl)butyric acids, 1... 

I - Alkyny lphenyl selenides. Benzeneselenenyl bromide and silver nitrite (1 equiv.) rcncl to form a reagent (presumably C6H5SeN02) that converts 1-alkynes into 1-nlkynyl phenyl selenides (equation I).1 The same reaction has been effected in generally lower yields with phenyl selenocyanate catalyzed by Cu(I).2 The products tire useful intermediates for regio- and stereoselective synthesis of vinyl selenides. 

Phenyl selenocyanate reacts with the 4-morpholinyl enaminc derived from propanal giving fram -2-(4-morpholinyl)-3-(phenylseleno)butancnitrile (73) stereoselectively 70. 

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]. 

Cyanoselenation of aldehydes with phenyl selenocyanate in the presence of BusP gave a-(arylsele-no)nitriles. Selenylation of nitriles aSiST treatment with 2 equiv. of base also led to the formation of a-selenonitriles. Their lithiated derivatives undergo smooth alkylation with methyl iodide (80%) and Michael addition to cyclohexenone in 90% yield (Scheme 30). ... 

Since phenyl selenocyanate (25 Ar = Ph) is a sensitive liquid, which slowly decomposes on storage during a few days, an improved method using A -phenylselenophthalimide (A -PSP 27), a stable crystalline compound, has been developed. In general, the yields of selenol esters prepared from N-PSP/BuaP are higher than those obtained employing ArSeCN/BusP. 

Phenylpropionaldehyde, 271 Phenyl selenides, 238 Phenylselenoacetaldehyde, 310-312 Phenylselenoacetone, 311, 312 Phenyl selenocyanate, 56 Phenylselenoetherification, 18 N-Phenylselenophthalimide, 312-313... 

ALKENES Allyl dimethyldithiocarbamate. Bis(t -cyclopentadienyl)niobium trihydride. Cyanogen bromide. Di-n-butylcopperlithium. a,o-Dichloromethyl methyl ether. 2,3-Dimethyl-2-butylborane. N,N-Dimethyl dichlorophosphoramide. Diphenyl diselenide. Di-n-propylcopperlithium. Ferric chloride. Grignard reagents. Iodine. Lithium phenylethynolate. Lithium 2,2,6,6-tetramethylpiperidide. Methyl iodide. o-Nitro-phenyl selenocyanate. Propargyl bromide. rra s-l-Propenyllithium. Selenium. Tetrakis(triphenylphosphine)palladium. Titanium(IH) chloride. Titanium trichloride-Lithium aluminum hydride. p-Toluenesulfonylhydrazine. Triphenylphosphine. Vinyl-copper reagents. Vinyllithium. Zinc. 

Bridged ethers can readily be prepared by the electrophilic attack of various organoselenium reagents on olefins. Nicolaou and his group " have given full details of the attack of selenohalides on unsaturated alcohols (Scheme 21), and oxyselenation of dienes is also effective (Scheme 22). If phenyl selenocyanate is used in the presence of cupric chloride, as the electrophile, the product ratio (123) (124) is strongly solvent-dependent. As the organoselenium substituent... 

Phenyl selenocyanate, CoHsSeCN. Mol. wt. 182.08, b.p. 125°/16 mm. Preparation. Selenol esters, RCOSeCeH. Carboxylic acids react with phenyl selenocyanate (1 equiv.) and tri-n-butylphosphine (2 equiv.) in methylene chloride or THF to form phenylselenol esters usually in high yield. Similarly, thiol esters,... 

Phenyl selenocyanate can also be used in this reaction, but not phenylselenenyl chloride, di-o-nitrophenyl diselenide, or diphenyl diselenide. ... 

A standard condition has been optimized for this reaction, in which the aryl amine is diazotized in 10 times its amount of acetic acid, followed by the addition of one equivalent of cuprous halide in hydrohalic acid. Under these conditions, the acetate salt of aryl amine is relatively soluble, and less froth and tarry material are formed during diazo transformation. In addition, chlorination, bromination, and iodonation of p-haloaniline to dihalobenzenes under such standard conditions give almost comparable average yields. Other modifications of this reaction include the formation of phenyl selenocyanate by the reaction with potassium selenocyanate, and aryl nitrile by the reaction with nickel cyanide. Moreover, this reaction has been extended to the preparation of phenyl thiocyanate, phenyl isothiocyanate and aromatic sulfonyl chloride. ... 

Phenyl selenocyanate added to a mixture of BujP and startg. alcohol in THF, and allowed to react at room temp, for 4 h (cf. Synth. Meth. 32, 599) - intermediate selenide (Y 88%), in benzene treated with PhjSnH and a little AIBN in one portion, and refluxed for 1 h product (Y 92%). F.e. inch photochemically initiated ring opening, and prepn. of startg. m., s. D.L.J. Clive, S. Daigneault, J. Chem. Soc. Chem. Commun. 1989, 332-5. 

Phenyl selenocyanate is an important reagent for organic synthesis, capable of a wide variety of selenylation reactions. Until now the method of preparation has employed a diazo reaction however, in a new synthesis benzeneselenyl chloride reacts with trimethylsilyl cyanide to give phenyl selenocyanate in quantitative yield (Scheme 54). Since isolation simply involves evaporation of the solvent, this reaction represents a very simple synthesis of the useful reagent. 

Pyridyl)phenyl selenocyanates are the products of the thermal or photochemical rearrangement of 2,1,3-benzoselenadiazoles. ... 

New methods for preparing known selenium reagents are always interesting. For example, phenyl selenocyanate is readily prepared by addition of trimethyl-silylcyanide to phenylselenyl chloride. Two new preparations of sodium phenylselenide have also appeared. In the first, selenide ion is photolysed in the presence of iodobenzene, whereas the second preparation involves... 

In a similar vein, the 1,2-cyanoselenylation of olefins has been observed for the first time in the reaction of phenyl selenocyanate with enamines/ and has been extended to reactions with ketene acetals and simple olefins." In the latter example, the addition of phenyl selenocyanate to unactivated olefins proceeds stereoselectively in the presence of a Lewis acid catalyst and, as in the above cyanosulphenylation procedure, elimination provides the corresponding alk-2-enenitriles (Scheme 32). 

Finally, phenyl tellurocyanate reacts with alcohols, ROH, to give tellurides RTePh in 32—78 % yields in a reaction which is analogous to that of phenyl selenocyanate. ... 

Related Reagents. Copper(II) Chloride Copper(II) Chloride-Copper(II) Oxide lodine-Copper(II) Chloride Copper(I) Chloride-Oxygen Copper(I) Chloride-tetrabutylammonium Chloride Copper(I) Chloride-Sulfur Dioxide lodine-Alutninum(III) Chloride-Copper(II) Chloride lodine-Copper(I) Chloride-Copper(II) Chloride Methylmagnesium lodide-Copper(I) Chloride Palladium(II) Chloride-Copper(I) Chloride Palladium(II) Chloride-Copper(II) Chloride Phenyl Selenocyanate-Copper(II) Chloride nyl-magnesium Chloride-Copper(I) Chloride Zinc-Copper(I) Chloride. 

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