A. V. Martynov

Cross-coupling of (Z)-1,2-bis(ethylseleno)ethene with the Grignard reagents

Abstract The nickel-catalyzed cross-coupling of (Z)-1,2-bis(ethylseleno)ethene with the alkyl magnesium bromides proceeds with substitution of both ethylseleno groups to afford symmetrical alkenes, (Z)-RCHCHR, in high yield with complete retention of configuration. In the case of phenyl magnesium bromide the monoarylation occurs to form (Z)-2-ethylseleno styrene, EtSeCHCHPh.

Synthesis of E,E-bis(chloromethylidene) derivatives of N-organylthiomorpholines and -selenomorpholines and their quaternary salts

An efficient method for preparation of hitherto unknown E,E-bis(chloromethylidene) derivatives of -organylthiomorpholines and -selenomorpholines by the reaction of E,E-bis(3-bromo-1-chloro-1-propen-2-yl) sulfide and selenide with primary amines in benzene or THF as well as with ethylammonium bromide in ethanol in the presence of Na2CO3 has been described. Heterocylization of the above sulfide and selenide by reaction with diethylamine in THF affords the unknown E,E-bis(chloromethylidene) derivatives of heterocyclic quaternary salts-4,4-diethyl-1,4-thiazinan-4-onium and -1,4-selenazinan-4-onium bromides. GRAPHICAL ABSTRACT

Synthesis of new heterocycles by oxidation of functionalized cyclic derivatives of bis(2-chlorovinyl) sulfide and selenide

Oxidation of 4-substituted 2,6-bis[(E)-chloromethylidene]thiomorpholine with hydrogen peroxide in a mixture of chloroform with acetic acid afforded the corresponding 4-R-2,6-bis[(E)-chloromethylidene]-thiomorpholine 1-oxide. The results of oxidation of bis[(E)-chloromethylidene]-1,4-dichalcogenanes under analogous conditions depended on the chalcogen nature and its position in the ring. The reaction of 2,6-bis[(E)-chloromethylidene]-1,4-dithiane gave 2,6-bis[(E)-chloromethylidene]-1,4-dithiane-1,1,4,4-tetraone, whereas 3,5-bis[(E)-chloromethylidene]-1,4-thiaselenane-1,1-dione was unexpectedly obtained from 3,5-bis[(E)-chloromethylidene]-1,4-thiaselenane. 2,6-Bis[(E)-chloromethylidene]-1,4-thiaselenane and 2,6-bis[(E)-chloromethylidene]-1,4-diselenane decomposed under the oxidation conditions.

BIS-E-CHLOROMETHYLIDENE DERIVATIVES OF 4-THIO- AND 4-SELENOMORPHOLINAMINES

It is known that the reaction of bis(2-haloethyl) sulfides with substituted amines gives 4-thiomorpholine and its N-substituted derivatives [1], while the reaction with hydrazine hydrate yields 4-thiomorpholinamine [1, 2]. 4-Selenomorpholinamine is unknown, but 4-selenomorpholine and a series of its N-substituted derivatives have been reported [3, 4]. We have developed a general method for the preparation of the previously unknown bis-E-chloromethylidene derivatives of 4-thiomorpholinamine 3 and 4-selenomorpholinamine 4. The method is composed of two stages, the first of which is a stereoand regioselective reaction of sulfur or selenium dichloride with propargyl bromide, occuring as an anti-Markovnikov addition to give the E,E-bis(3-bromo-1-chloro-1-propen2-yl) sulfide (1) or selenide (2) in high yields [5, 6]. The second stage is a chemoselective nucleophilic substitution of the bromine atoms in the bromomethylene fragments of sulfide 1 and selenide 2 with hydrazine hydrate in the presence of NaOH to give the heterocycles 3 and 4 in high yields. This second stage includes the alkylation of one hydrazine amino group with two bromomethyl groups of the divinylchalcogenides 1 and 2, giving the unsymmetrical 1,1-disubstituted hydrazine derivatives, which is a typical feature of the reaction between hydrazine and alkyl halides [7].

Selenium and sulfur dichlorides as chlorinating agents in the reaction with alkyl 2,2-dichlorovinyl sulfides

The chlorination of vinyl sulfi des with free chlorine is known to proceed with so large heat evolution that the reaction products suffer spontaneous dehydrochlorination [1]. At the same time the chlorination of phenyl 2,2-dibromovinyl sulfi de with chlorine occurred with the substitution of bromine and/or hydrogen atoms for chlorine and with the cleavage of the S–C bond and afforded a complex mixture of substances lacking products of chlorine addition to the double bond [2]. The chlorination of 2,2-dichlorovinyl sulfi des with free chlorine was not known, but in keeping with [2] the formation in this reaction of the corresponding saturated adducts, 1,2,2,2-tetrachloroethyl sulfi des was hardly probable. These sulfi des formed in a quantitative yield in two-stage reactions proceeding from chloral and thiol [3]. We found that the introduction of chlorine atoms to the double bond of dichlorovinyl sulfi des (I) could be effi ciently performed by treating with selenium dichloride, a selenylating agent that with divinyl sulfi de [4], divinyl selenide [5], and divinyl sulfone [6], and also with bis(2chlorovinyl) selenide [7], the other representative of chlorovinyl chalcogenides, reacted along the electrophilic addition mechanism leading to the formation of four-, fi ve-, and six-membered heterocycles. Only with divinyl telluride the selenium dichloride acted as a chlorinating agent, but here the chlorination proceeded no at the double bond, but at the tellurium atom resulting in oирование идет не по двойной связи, а по атому теллура с образованием divinyltellurium dichloride [8]. The sulfur dichloride, the known sulfi nating agentwidely used in the syntheses of various saturated sulfi des and sulfur heterocycles [9] also behaves as a chlorination agent in the reaction with alkyl 2,2-dichlorovinyl sulfi des. In keeping with results of [4–7, 9] the most probable direction of the reaction of selenium and sulfur dichlorides with vinyland chlorovinyl chalcogenides is the electrophilic addition, and the results we have obtained are quite unexpected. The reaction of selenium dichloride generated in situ from selenium and sulfuryl chloride with dichlorovinyl sulfi des Ia, Ib was carried out in chloroform at room temperature in the presence of 16–23 mol% of catalyst, AlCl3 or FeCl3, and resulted in 17–36 h in the formation in high yields of alkyl 1,2,2,2-tetrachloroethyl sulfi des IIa, IIb (Scheme 1) that were purifi ed by column chromatography on silica gel eluting with hexane. The reaction did not occur in the absence of the catalyst. The initial isopropyl (Ia) and hexyl (Ib) 2,2-dichlorovinyl sulfi des were obtained by the reaction of trichloroethylene with the corresponding thiol [3].

Regioselective addition of sulfur dichloride and selenium tetrachloride to diallyldimethylsilane as the method of preparation of eight-membered heterocycles containing silicon and chalcogens

The electrophilic additiob of sulfur dichloride and selenium tetrachloride to diallyldimethylsilane proceeds strictly according Markownikoff rule and results in the formation of previously unknown saturated siliconcontaining heterocycles, 5,5-dimethyl-3,7-dichloro-1,5-thiasilacyclooctane and 5,5-dimethyl-1,1,3,7-tetrachloro-1,5-selena(IV)silacyclooctane. The structure of heterocycles obtained was confi rmed by 1H, 13C NMR spectra, in the case of selenium-containing heterocycle, by 77Se NMR spectrum, among them the 2D HMBC spectrum.

Electrophilic addition of selenium and telluriom halides to methyldiethynylsilane

Regio- and stereoselective electrophilic addition reactions of SeCl2, SeBr2, SeCl4, SeBr4 to methyldiethynylsilane lead to predominant formation of the Z-isomers of 3,6-dihalo-4-methyl-1,4-selenasilafulvenes, disiloxanes on their bases, as well as disiloxanes formed upon the reaction with methyldiethynylsilane. TeCl4 reacts with methyldiethynylsilane with predominant formation of the E-isomer of 1,1,3,6-tetrachloro-1-methyl-1-(methyldiethynylsiloxy)-1,4-tellura(IV)silafulvene as a result of the reaction of the intermediate E-isomer of 4-methyl-1,1,3,6-tetrachloro-1,4-tellura(IV)silafulvene with methyldiethynylsilane. The structure of the products was proved by the methods of 1H, 77Se NMR, IR spectroscopy and chromatomass spectrometry.

Reaction of dimethyldiethynylsilane with 1,2-dichlorodiselane

In continuation of our studies of the reactions of selenium halides with bridged diacetylenes, like diorganyldiethynylsilanes R2Si(C≡CH)2 and -germanes R2Ge(C≡CH)2, leading in the case of SeCl2 and SeBr2 to the five-membered unsaturated selenium, siliconand selenium,germanium-containing heterocycles having the fulvene structure [1–3], we have studied the reaction of dimethyldiethynylsilane with 1,2-dichlorodiselane Se2Cl2. Addition of Se2Cl2 to terminal acetylenes in DMF is known to result in the formation of diselenides by the mechanism of anti-addition [4], while the reaction with phenylacetylenes PhCoCR is followed by intramolecular cyclization with elimination of selenium and formation of benzoselenophenes [4]. With acetylene, Se2Cl2 also reacts with elimination of selenium and formation of the E-isomer of 2-chloroethenylselenenylchloride [5]. In a similar manner, that is, with elimination of sulfur, proceeds the reaction of sulfur monochloride S2Cl2 with two molecules of diphenylacetylene leading to the substituted divinylsulfide rather than the anticipated disulfide [6].

First example of the anti-Markownikoff addition of tellurium tetrachloride to terminal acetylene, trimethyl ethynyl silane

Abstract(μ2-Oxo)-bis[dichloro(Z-2-chloro-1-trimethylsilylethenyl)tellurium(IV)] (III) was prepared by electrophilic addition of TeCl4 to trimethylethynylsilane in CHCl3 at room temperature. The reaction is the first example of the anti-Markownikoff type addition of TeCl4 to terminal acetylenes affording as an intermediate the 1:1 adduct [Z-1-(trimethylsilyl)-2-chlorovinyl]tellurium trichloride (II). The latter is converted into III by a sequence of successive reactions of hydrolysis and dehydration. The structure of compound III was proved by the of multinuclear (1H, 13C, 29Si, 125Te) NMR spectroscopy and XRD analysis. Compound III is the first example of structurally characterized C-TeCl2-O fragment.

Chlorochalcogenation of acetylenes with benzenesulfen-(or selenen)amides and Tin(IV) chloride

Benzenesulfenamides and benzeneselenenamides reacted with terminal and internal acetylenes (hex-1-yne, phenylacetylene, hex-3-yne, but-2-yne-1,4-diol, and diphenylacetylene) in the presence of SnCl4 to give the corresponding chloroethenyl sulfides and selenides. From symmetric acetylenes, only E isomers (E)-ArXCR=CClR (X = S, Ar = Ph, 4-ClC6H4; R = Et, Ph, HOCH2; X = Se, Ar = Ph, R = Et) were formed. The reactions of benzenesulfenamide with terminal acetylenes, apart from the corresponding Markownikoff and anti-Markownikoff adducts (PhSCH=CClR and PhSCR=CHCl, R = Bu, Ph) gave ethynyl sulfides PhSC=CR (R = Ph, Bu) and cis/trans-isomeric 1,2-bis(phenylsulfanyl)chloroethenes PhSCR=CClSPh (R = Ph, Bu). The results were interpreted assuming intermediate generation of sulfenyl and selenenyl chlorides via reaction of sulfen-and selenenamides with SnCl4.