Silicon-nitrogen reagents

In spite of the hazardous nature of Sc4N4, this binary selenium nitride has been used for the synthesis of other Se-N compounds, all of which have sulfur analogues (Scheme 5.2). " However, safer alternatives to the use of Sc4N4, e.g., selenium-nitrogen halides and silicon-nitrogen-selenium reagents, are available for the development of Se-N chemistry. ... 

Synthesis of Phosphorus-Nitrogen Polymers by Using Silicon-Nitrogen-Phosphorus Reagents... 

Insertion of the Si=N bond into polar bonds is the most used reaction for the characterization of very reactive and transient silanimines. Especially, the reaction with alcohols is often the first reaction to be carried out with silicon-nitrogen multiple bond systems. Other reagents used for insertion reactions are amines, water and alkoxysilanes (equation 269)300,303,306,311,351-353. The insertion into E—X bonds (E = Si, Ge, Sn X = Cl, OR, NR2, N3) has been shown earlier in this review for the insertion into the Si—N bond of silyl azides310,351. A reaction reported is the insertion of 678 into the C—H... 

Amino, alkoxy, and aryloxy polyphosphazenes are typically prepared by nucleophilic displacement reactions of poly(dihalophosphazenes). Analogous reactions with organometallic reagents, however, result in chain degradation and cross linking rather than in linear, alkyl, or aryl substituted poly(phosphazenes). The thermolysis of appropriate silicon-nitrogen-phosphorus compounds can be used to prepare fully P—C bonded poly(organophosphazenes). The synthesis of two of these materials and their Si—N—P precursors is described here. 

An important silicon-nitrogen compound is hexamethyldisilazane or HMDS. This reagent is an effective silylating agent and has found wide applicability assisting in the volatilization of temperature-sensitive alcohol. The silylation process is characterized by the following generalized equation (Equation 21) ... 

Use of dimethoxydiphenylsilane in combination with N,N-dimethylformamide-p-toluenesulfonic acid to introduce silicon into the sucrose molecule has been exploited.27 On treatment with this combination of reagents, sucrose gave, after chromatographic fractionation of the acetylated mixture, 3,4,6,3, 4, 6 -hexa-0-acetyl-2,l -0-(diphenylsilyl)sucrose (10) and 3,4,3, 4 -tetra-0-acetyl-2,l 6,6 -di-0-(diphenylsilyl)sucrose (33) in 45 and 10% yield, respectively.27 With a view to introducing other heteroatoms, such as phosphorus or nitrogen, into the sucrose molecule, such reagents as dimethoxy-phenylphosphine, N,N-dimethylformamide dimethyl acetal, and 3,3-dimethoxypropylamine in combination with 2V,N-dimethylfor-mamide-p-toluenesulfonic acid are of interest. 

Notes. (1) The editors suggest that the apparatus consists of a 100-ml two-necked flask fitted with a silicone rubber septum into which is inserted a syringe needle connected to a nitrogen feed (Section 2.17.8, p. 120) and through which the reagents may be syringe-injected the second arm of the flask is fitted with a reflux condenser the outlet of which is connected to a mercury bubbler. 

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