Disilathiane

Introduction of trimethylsilyl substituents attached directly to the ot-carbon atom of a-(benzotriazol-l-yl)alkyl thioethers provide new opportunities. Thus, treatment of lithiated monosubstituted a-(benzotriazol-l-yl)alkyl thioethers with chlorotrimethylsilane produces a-(trimethylsilyl)alkyl thioethers 837. In reactions with hexamethyl-disilathiane and cobalt dichloride, thioethers 837 are converted to thioacylsilanes 838 that can be trapped in a Diels-Alder reaction with 2,3-dimethylbutadiene to form 2-alkyl-4,5-dimethyl-2-trimethylsilyl-3,6-dihydro-27/-thiopyrans 839 (Scheme 133) <2000JOC9206>. 

Disilathiane has been the subject of several recent studies.1 7 Interest has been centered on the importance of (p-d)7r-bonding in determining both the structure and the base strength relative to the disiloxanes and carbon analogues.2 6 The utility of disilathianes has been demonstrated by their conversion to a wide variety of silyl derivatives by exchange reactions or protolyses.2,7... 

Disilathianes, for example (SiH3)2S and [(CH3)3Si] 2S, have been prepared by several routes, namely, the reaction of iodosilane with silver8 and mercuric2 sulfides halosilanes with lithium sulfide,7 [NH4]SH,9 and [Me3NH]SH7 disilaselenane with H2S10 and trisilylphosphine with sulfur.10 Recently, the synthesis of hexamethyldisilathiane, [(CH3)3Si] 2S, was described from the protolysis of l-(trimethylsilyl)imidazole with H2S and from the dehydrohalogen-ation of chlorotrimethylsilane and H2S with a tertiary amine.11 Both of these methods require about 18 hours. 

The syntheses of disilathiane and its methylated analogues by the reaction of mercuric sulfide with gaseous iodosilanes is described here in detail. The procedures are convenient, take about 2 hours, and are well suited to small-scale vacuum-line techniques, using a minimum of special appartus. The yields are in the range of 90-95%. 

The checkers have prepared disilathiane and hexamethyldisilathiane in high yield by reacting the appropriate tertiary and secondary amine with H jS for 2 hr and then treating the solid residue with an excess of the appropriate chlorosilane or bromosilane. 

Caution. The disilathianes should be regarded as toxic and are vile smelling. Their exposure to air and/or moisture is likely to promote rapid oxidation. Manipulations should be carried out in a sound vacuum system in a well-ventilated area. All preparations may be scaled-up to use 10 mmole of starting material. 

The synthesis of isothiazole-fused sulfone 265 is based on the same approach and was obtained from sulfolene 520 (see Section 4.05.7.3) <1996TL4189>. Treatment of different heterocyclic n-azidocarbaldehydes with hexamethyl-disilathiane (HMDST) in the presence of HCl as catalyst offers a novel and practicable route to fused isothiazoles 521-523 <1997PS(120)165, 2005SL1965, 2000EJ02171>. 

In contrast to the afore-mentioned types of compounds, unsubstituted silanethiol (730) can be obtained either by treatment of disilathiane (729) (for preparation of 729 see Section XII, B.2 below) with H2S418 (equation 373) or via the reaction of chlorosilane (731) with alkali- or magnesium hydrogen sulphides (equation 374)419. 

Non-symmetrically substituted hexaorganyldisilathianes can be synthesized from halotriorganylsilanes and sodium triorganylsilanethiolate (equation 381)420. A convenient way to accomplish the synthesis of symmetrical disilathianes (733) with bulky... 

The synthesis of hexamethyldisilathiane from sodium sulfide and chloro-trimethylsilane is described here. The present method is based on the convenient in situ syntheses of alkali metal selenides and diselenides. Commercial sodium sulfide or lithium sulfide are reported to be poor substitutes for in situ generated sulfides in this reaction. For example, in 1961 Abel reported that disodium sulfide reacts with chlorotrimethylsilane in pressure vessels at 250°C for 20 h to produce I. Our procedure is very convenient, utilizing readily available starting materials and apparatus under mild conditions. The yields are t3q)ically 80-88% at 0.3-mol scale. However, it can be improved to 90-95% on small scale ( 50-mmol) reactions. This procedure can be applied to the synthesis of various disilathianes. 

SPCjH, Phosphine sulfide, dimethyl-, and manganese complex, 26 162 SPOjC 4H2o. 2H-l,2-Thiaphosphorin-2-ium, 3,4,5,6-tetrakis(methoxycarbonyl)-2,2-dimethyl-, manganese complex, 26 165 SSi2C6H3o, Disilathiane, hexamethyl-, 29 30 S2, Disulfido, chromium complex, 29 252 S2BOP3RhC ,Hs Rhodium(III), [[2-[(di-phenylphosphino)methyl]-2-methyl-... 

Si2SCjH3o, Disilathiane, hexamethyl-, 29 30 Si C 10H2J, Methane, tris(trimethylsilyl)-, 27 238... 

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