42572-42-9

A second polymorph of phenyl-selenium trichloride, PhSeCl3 or C6H5Cl3Se, is disclosed, which is comprised of asymmetric chlorine-bridged noncovalent dimer units rather than polymeric chains. These dimers are each weakly bound to an adjacent dimer through

The preparation of a series of 1:1 adducts of organoselenium and -tellurium trichlorides with antimony pentachloride is reported. These compounds are colorless or pale yellow moisture-sensitive crystalline solids. The adducts are soluble in CH2Cl2, insoluble in nonpolar organic solvents, and rapidly decomposed by donor organic media. The solid-state infrared spectra are interpreted in terms of the formulation [RMCl2+][SbCl6-], where M = Se, Te. Proton magnetic resonance data on these compounds are discussed.

The first example for the electrochemical cis-dichlorination of alkenes is presented. The reaction can be performed with little experimental effort by using phenylselenyl chloride as catalyst and tetrabutylammoniumchloride as supporting electrolyte, which also acts as nucleophilic reagent for the SN2-type replacement of selenium versus chloride. Cyclic voltammetric measurements and control experiments revealed a dual role of phenylselenyl chloride in the reaction. Based on these results a reaction mechanism was postulated, where the key step of the process is the activation of a phenylselenyl chloride-alkene adduct by electrochemically generated phenylselenyl trichloride. Like this, different aliphatic and aromatic cyclic and acyclic alkenes were converted to the dichlorinated products. Thereby, throughout high diastereoselectivities were achieved for the cis-chlorinated compounds of >95 : 5 or higher.

Solid state structures of selenium(IV) compounds PhSeX3 (X=Cl, Br) were compared. Crystals of PhSeX3 (X=Cl, Br) were produced by recrystallization from refluxing diethyl ether. The structure of PhSeCl 3 showed polymeric ch

α-Phenylselanyl aldehydes are prepared on a large scale by reaction of PhSeCl3 with the corresponding aldehydes in acetonitrile without isolation of the intermediate dichloro adducts. This method has been applied to α-phenylselanyl ketones deri

Phenylselenium trichloride (1) is prepared from benzeneseleninic acid (2) and thionyl chloride and used to effect vinylic chlorination, viz. the conversion of 3-chloro-2-chloromethyl-1-propene (4) into 2-chloromethyl-1,3-dichloropropene (3).

Chlorination of α-seleno-aldehydes bearing an α-hydrogen gives selenium dichlorides which decompose into α-chloro α-seleno-aldehydes and α-chloroenal.Bromination, in all cases, and chlorination for the other α-seleno-aldehydes lead to the α-halogenoaldehydes.

Phenylselenium trichloride, PhSeCl3, was reacted with a number olefinic compounds to produce (β-chloroalkyl)phenylselenium dichlorides.The addition was anti stereospecific and irreversible.The presence of an oxygen substituent (acyloxy or aryloxy group) in the allylic position of the olefin directed the attack of PhSeCl3 to occur regiospecifically anti-Markovnikov to give a (β-acyloxy/aryloxy-β'-chloroalkyl)phenylselenium dichloride.When the (β-chloroalkyl)phenylselenium dichlorides were treated in methylene chloride with aqueous sodium hydrogen carbonate, the selenium dichloride moiety was readily hydrolyzed to a selenoxide, which underwent the usual selenoxide elimination reaction to produce an allylic or a vinylic chloride.Symmetrical olefins containing no allylic hydrogens were converted to vinylic chlorides with retention of olefin geometry.Olefins containing a directing oxygen substituent in the allylic position afforded vinylic chlorides where the vinylic halogen atom was oriented 1,3 to the oxygen substituent (E/Z mixture).Other olefins afforded mixtures of allylic and vinylic halides in varying proportions.The reaction of phenyselenium tribromide, PhSeBr3, with some olefinic compounds was also investigated.This material showed the same stereo- and regiochemical behavior as PhSeCl3 in its addition reactions.However, the adducts were not useful for the preparation of vinylic or allylic bromides by using the hydrolytic selenoxide elimination reaction.

Phenyl selenium trichloride was used for the introduction of a PhSeCl2-group into the α-position of ketones.These products were converted to enones (hydrolysis/selenoxide elimination) or α-phenylselenoketones (thiourea-reduction).

N-Aryldichloroselenoareneseleninimidoyl chlorides are obtained by the reaction of equimolar amounts of arylselenium chloride, arylselenium trichloride , and N-chlorohexamethylsilazane.They are also obtained in the reaction of arylselenium trichlorides with N-chlorohexamethyldisilazane or hexamethyldisilazane.

The reaction of arylselenium chlorides with N-chloro derivatives of morpholine, benzotriazole, succinimide, phthalimide, imidic esters, and ketimines leads to the formation of compouds of tetracoordinated selenium, i.e. arylaminoselenium dichlorides.The same compounds are obtained in the reaction of arylselenium trichlorides with N-trimethylsilylamines of the R2NSiMe3 type.

N-Acylseleninimidoyl chlorides were obtained by the reaction of diaryl diselenides, arylselenosilanes, or arylselenium chlorides with the dichloroamides of carboxylic acids.The acid chlorides react with styrene by a scheme of 1,4-cycloaddition with the formation of 4-chloro-2,4,6-triaryl-5,6-dihydro-4-selena-1,3-oxazines.