Reaction of selenium dichloride with allyl phenyl ether

Abstract

SHORT COMMUNICATIONSIn the recent years, a new synthetic approach to organoselenium compounds on the basis of selenium dichloride and selenium dibromide is extensively developed . Reactions of selenium dichloride and selenium dibromide with compounds possessing two double [4][5][6][7][8][9][10][11][12][13][14][15][16][17] or triple bonds [1-3] provide efficient methods for the synthesis of new heterocyclic systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Reactions of selenium dichloride and selenium dibromide with divinyl sulfide [4][5][6][7][8][9], divinyl sulfone [10][11][12][13], and divinyl selenide [14-17] afforded previously unknown four-, five-, and six-membered heterocycles containing two chalcogen atoms.We recently showed that selenium dihalides can act as electrophilic reagents in electrophilic aromatic substitution processes. Bis(4-methoxyphenyl) selenide was synthesized in high yield by reaction of selecnium dichloride with methoxybenzene [21]. The reaction was carried out by heating the reactants in boiling chloroform. An important condition ensuring successful reaction is the use of arene activated by an alkoxy group. Insofar as selenium dichloride is capable of both adding at a double bond and acting as electrophile, a combination of these reactions could lead to fused heterocyclic compounds.In fact, by reaction of selenium dichloride with allyl phenyl ether we obtained a new heterocyclic compound, 3-chloromethyl-2,3-dihydro-1,4-benzoxaselenine (I) in 75% yield. The reaction was carried out with equimolar amounts of the reactants in chloroform. The best result was obtained by mixing the reactants at low temperature (-60°C) with subsequent heating of the reaction mixture to 50-60°C. Presumably, the addition of selenium dichloride at the allyl group occurs at low temperature, whereas the second step, electrophilic aromatic replacement, requires elevated temperature (50-60°C). The reaction is regio-and stereoselective. This may be due to formation of intermediate seleniranium ion A; attack by chloride ion on the latter at the methylene carbon atom with formation of anti-Markovnikov adduct B is more favorable.The structure of compound I was determined by 1 H, 13 C (including JMOD technique), and 77 Se NMR spectroscopy, mass spectrometry, and elemental analysis. The coupling constant between the selenium atom and CH carbon atom in the propyl fragment corresponds to direct Se-C interaction ( 1 J C,Se ), which indicates that selenium adds to the central carbon atom of the allyl group.It should be noted that Migalina et al. [22] previously described the reaction of selenium tetrachloride with allyl phenyl ether, which did not lead to cyclization product but afforded the corresponding open-chain Markovnikov adduct, dichlorobis(2-chloro-3-phenoxypropyl)-λ 4 -selane.Thus we were the first to demonstrate that addition of selenium dichloride at double bond can be accompanied by electrophilic aromatic substitution with formation of fused heterocyclic system.3-Chloromethyl-2,3-dihydro-1,4...

Selenium– and tellurium–halogen reagents

“…A simple example is the formation of 3-bromo-2phenylbenzo[b]selenophene in 92 % yield from the reaction of SeBr2 with diphenylacetylene in diethyl ether at room temperature (Figure 2.5) [40]. Annulation is also observed in the reactions of SeX2 with thiophenenyl-substituted alkynes [41] and with unsaturated ethers [42,43]. The electrophilic addition of SeX2 to the triple bond of a large range of propargyl alcohols has also been investigated, including the formation of selenium-containing spiroketals with potential biological activity [44a, 44b].…”

Efficient Synthesis of a New Family of 2,6-Disulfanyl-9-selenabicyclo[3.3.1]nonanes

“…Currently organic synthesis based on selenium dihalides is an intensively developing area of research [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. Annulation reactions of selenium dihalides with unsaturated arenes gave various condensed heterocyclic compounds [ 40 , 41 , 42 , 43 , 44 ]. The addition of selenium dihalides to alkenes and alkynes afforded bis(2-haloalkyl) selenides [ 45 , 46 ] and bis(2-halovinyl) selenides in high yields [ 47 , 48 , 49 , 50 , 51 , 52 ].…”