Silyl Phosphites, Phosphonites and Phosphinites

R3SiO RoSiO —p / RjSiO R3SIO P-R R3SIO R3SIO — p R (9.281) 

Silyl phosphite Silyl phosphonite Silyl phosphinite  

Silyl phosphites such as (EtO)2POSiMe3 and (Et3SiO)3P are known. The latter compound can be prepared in 30% yield by reacting phosphorus tribromide with an organosilane in the presence of zinc chloride (9.282). Esters of the former type can be made by reaction (9.283). 

Trialkylhalosilanes can be used to obtain mono, di and tri-silyl esters (9.284-9.286). Reactions of this type are more complex than indicated if the alkyl halides are not qnickly removed. 

Tris(silyl)phosphites undergo Arbusov-type reactions (9.287). In a mixed phosphite ester, the alkoxy carbon is preferentially attacked (9.288). The silyl ester products are hydrolysed to phos-phonic acids (9.289). 

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