285. Interaction between phosphorus halides and alkoxytrimethylsilanes

Abstract

Stepwise replacement of halogen in phosphorus trihalides has been effected by alkoxytrimethylsilanes, thus avoiding the presence of hydrogen halides or tertiary base. The 1-phenylethoxysilane afforded the dichloridite, but the tert.-butoxy-analogue gave only alkyl chloride. Replacement in the oxychloride proceeded to the dichloridate, and much more slowly to the chloridqe, and there was evidence of formation of n-butyl phosphorodibromidate from the oxybromide. Fission of the alkoxysilane occurred differently in the examples of the 1-phenylethyl and diphenylmethyl derivatives , the oxychloride affording alkyl chloride and trimethylsilyl phosphorodichloridate.REPLACEMENT of halogen in phosphorus trihalides and oxyhalides by the alkoxyl group has been effected by alkoxytrimethykilane under conditions in which the presence of a tertiary base and a hydrogen halide is avoided. Certain limitations have been observed. Thus stepwise replacement of halogen in the trichloride by alkoxyl was effected by n-butoxytrimethylsilane , giving the alkyl phosphorodichloridite, the dialkyl phosphorochloridite, and the trialkyl phosphite [scheme (l)] . n-, iso-, and sec.-Butyl phosphorodibromidites, and the corresponding bromidites were prepared from phosphorus tribromide. The halogenotrimethylsilane formed concurrently was readily separated and used for the preparation of further supplies of the alkoxysilane.

Iron-Catalyzed Chlorination of Silanes

“…A variety of chlorinating agents and methods have been reported earlier for the chlorination of methoxysilanes, including acyl chloride, , thionyl chloride, , phosphorus trichloride, , phosphorus pentachloride, and oxalyl chloride with aluminum trichloride based methodologies. A zinc-catalyzed method derived from the deprotection of alcohols has been described involving zinc-catalyzed activation of Si–O bonds to generate esters and chlorosilanes .…”

The synthesis of chlorosilanes from alkoxysilanes, silanols, and hydrosilanes with bulky substituents

“…To date, many methods for the conversion of trialkylalkoxysilanes into trialkylchlorosilanes have been reported. In these methods, acylchloride [2], thionyl chloride [3], phosphorus pentachloride [4], phosphorus trichloride [5], tetrachlorosilane [6], and also hydrogen chloride gas [6,7] have been used as chlorinating agents. However, no suitable method for the industrial synthesis of the chlorosilanes from the alkoxysilanes is available so far.…”

Untitled

“…Die Trimethylsilylierung von 5 zu 6 mit Hexamethyldisilazan und Trimethylsilylchlorid [7] und die nachfolgende Bromwasserstoff-Abspaltung mittels 1.5-Diazabicyclo[4.3.0]nonen- (5) (DBN) führt zu 7, das sich bei 20 °C mit P0C13 in 24 h zum Dichlorphosphat (3) umsetzt [8].…”