Selenyl chlorides

Selenium Nitride (Nitrogen Selenide). Se4N4, mw 371.87, N 15,07%, yel-brick red hygr amorph powd, mp (expl 160—200°), bp (decompn). SI sol in hot w (decompn) v si sol in acet, acet ac, bz CS2. Methods of prepn include passing dry ammonia into a dil soln of selenyl chloride in bz, or into a cooled soln of selenium chloride in CS2 (Refs 1-5 7-10)... 

An exchange reaction between Se02 and SeCl4 produces selenyl chloride. 

Although such reactions must take place to only a very slight extent, autoionization of thionyl chloride and selenyl chloride is presumed to produce EOCl+ and FOCI, ions. The molecules are pyramidal in the gas phase, but there is extensive bridging between molecules in solid SeOCl2. 

Sulfenyl chlorides and halogens react with 1,2-alkadienylphosphonic acids to afford phosphorus-containing heterocydes [72], However, the electrophilic addition of dialkyl 4-methyl-2,3,5-hexatrien-2-yl phosphonates with sulfenyl or selenyl chloride afforded 2-thienyl methylphosphonates or the seleno analogues [73, 74]. The conjugate addition of sulfenyl or selenyl chloride with the 2,4-diene moiety in the starting allene leads to the formation of the five-membered skeleton (Scheme 10.69). 

If 3-chloro-N-nitrosopiperidine is used instead of the tosylate, 3,4-dehydro-N-nitrosopiperidine is formed in high yield. Another, perhaps more general, route to the vinylnitrosamines makes use of the acidity of the hydrogens on the a-carbon of nitrosamines (18). The resulting carbanion reacts smoothly with phenyl-selenyl chloride. The adduct is then oxidized with m-chloroper-benzoic acid (19). 

Selenyl Chloride, Selenium Oxychloride, SeOCl2, may be prepared in the following ways ... 

It may also be prepared by passing a stream of dry ammonia into a 2 to 4 per cent, solution of selenyl chloride in benzene.4 The nitride is precipitated as a buff-coloured solid which becomes orange-red when dry. Some free selenium is deposited along with the nitride, the amount increasing with the concentration of the selenyl chloride solution. After washing the buff precipitate the free selenium may be extracted by means of potassium cyanide solution. 

The 4,7-dimethoxy-2,2-dimethyl-l,3,2-benzodiselenastannole 321 was prepared from commercially available 1,4-dimethoxybenzene 320 by a sequence of tandem ortho-lithiation and selenation, and followed by dimethyltin protection in 28% yield (Scheme 51). Then, sequential treatment of the stannole 321 in THF with selenyl chloride, trimethylsilyl trifluoromethanesulfonate (TMSOTf), and samarium iodide gave crystalline 4,7-dimethoxybenzotri-selenole 42 in 75% yield <1996H(43)1843>. The structure was characterized by X-ray crystallographic analysis (Section 6.12.3.1). 

Selenium is a steel gray or purplish powder, also fabricated into pellets, sticks, or plates. Selenium dioxide, selenous acid, and the alkali-metal selenites and selenates are colorless powders or crystals. Selenium chloride (reddish yellow), selenyl chloride (colorless or yellow) (bp, 176°C), and selenic acid (colorless) are liquids, whereas selenium tetrachloride is a cream-colored crystalline solid.1... 

Ahnlich wie Alkyl- und Aryl-cyan-selenane (s. Bd. Xll/2, S. 838) reagieren auch Selenyl-chloride und -bromide mit Phosphorigsaure-di- und -triestern4 5 ... 

The synthesis of enantiopure thiazolines has been reported. The mixture of enantiomerically pure diastereoisomeric amido selenides 64, obtained from the reaction of camphorselenyl sulfate with trans alkenes, when treated with Lawesson s reagent affords a mixture of two thioamide derivatives 65a and 65b. The two diastereoisomeric thioamide selenides were easily separated by chromatography, each was then treated with phenyl selenyl chloride which caused deselenylation to occur in a stereospecific manner furnishing the thiazolines 66a and 66b in an enantiopure form <02TA429>. 

Selenyl chloride is the most important of the three selenium compounds having the formula SeOX2, and it has been used as a nonaqueous solvent. The liquids have substantial conductivity so it is presumed that some autoionization occurs in both SeOCl2 and SOCl2 ... 

Carbocyclic compounds can be formed by the nucleophilic intramolecular capture of a seleniranium intermediate of an olefinic bond. The carbonium ion which is formed as intermediate can react with another nucleophile or with the solvent. The first examples of these carbocyclization reactions were observed with dienes. Clive [105] reported that the reaction of the diene 203 with phenyl-selenyl chloride in acetic acid afforded the intermediate 204 which reacted with the solvent to give the bicyclic compound 205 (Scheme 31). Carbocyclization reactions were efficiently promoted by phenylselenyl iodide produced by diphenyl diselenide and iodine. As indicated in Scheme 31,Toshimitsu reported that the reaction of 1,5-hexadiene 206, in acetonitrile and water, afforded the acetamido cyclohexane derivative 209, derived from the cyclization of the seleniranium intermediate 207 followed by the reaction of the carbocation 208 with acetonitrile [106]. In several cases, carbocyclization reactions can be more conveniently effected by independently generating the seleniranium intermediates. A simple procedure consists of the reaction of trifluoromethane-sulfonic acid with j9-hydroxyselenides, which can be easily obtained from the... 

Both cholestan-3-one and cholestan-3-ol yield l,4-cholestadien-3-one on treatment with iodoxybenzene or m-iodoxybenzoic acid and a catalytic amount of benzeneseleninic anhydride, which is generated in situ from diphenyldiselenide [526], The treatment of cholestan-3-one with phenyl-selenyl chloride and hydrogen peroxide gives l-cholesten-3-one [167] (equations 31 and 32). 

Thus, trimethylsilyl ethers, such as 1, generated from cyclopropyl ketones, were reacted with a selenyl chloride as electrophile. 

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