Silylamines, reactions

These derivatives undergo ready reactions with silylamines ... 

Despite some of the melt fabrication problems, the organosiloxane systems produced by the silylamine-hydroxyl reaction ( ) produced interesting, perfectly alternating copolymers. 

Whereas most of the known silylamines containing both a silicon halogen and nitrogen hydrogen unit undergo rapid condensation with HC1 elimination [11], transition metal substitution of the silicon provides unexpected high thermal stability. Compounds of this type are available via reaction of the dichlorosilyl complexes 18a-c with bulky primary amines to generate 19a-c (Eq. (4)). 

Cleavage reactions of the silicon- nitrogen bond of silylamines by TeF6 affords aminotellurium(VI) fluorides (73, 74, 76) as in Eq. (13), where n = 1, 2 ... 

The quantitative nature of the silylamine-phenol reaction has been demonstrated for several different polymer systems (7). In our case, the charged PDMSX content was low to ensure that <1 phenolic group per novolac molecule reacted. This was done primarily to prevent extensive branching or crosslinking, and problems of insolubility and reproducibility associated with network formation... 

No free PDMSX should be found in these systems however, unreacted starting novolac will be present. Hence, each copolymer system consisted of a blend of novolac resin and novolac-PDMSX copolymer. Hie structure of these copolymer systems is complex. Since all phenolic groups possess equal reactivity towards silylamine groups, the difunctional PDMSX may react anywhere between two novolac chains (an A-B-A triblock species) or twice with the same novolac molecule. The second reaction type would yield a macrocyclic compound whose size would depend upon the proximity of the two phenolic groups to one another. 

The scope of nitrolysis is huge, with examples of nitramine formation from the cleavage of tertiary amines, methylenediamines, carbamates, ureas, formamides, acetamides and other amides. The deflnition of nitrolysis must be extended to the nitrative cleavage of other nitrogen bonds because sulfonamides and nitrosamines are also important substrates for these reactions. The nitrative cleavage of silylamines and silylamides is also a form of nitrolysis (Section 5.7). 

Millar and Philbin have explored the nitrodesilylation of silylamines with dinitrogen pen-toxide for the synthesis of nitramines and their derivatives. These reactions, which involve nitra-tive Si-N heteroatom cleavage, are conducted in methylene chloride at subambient temperature. Trimethylsilylamines give high yields of nitramine product and reactions are clean (Table 5.8). 

In contrast to 1,2-migrations between C and O, there are few reports on the Brook isomerization of a-silylamine (aza-Brook isomerization). The reaction of (a-silylallyl)amine 61 with n-C4H9Li in THF at low temperatnre followed by the addition of HMPA and CH3I gives the methylated prodnct 62 in qnantitative yield. These resnlts indicate that an aza-Brook isomerization occnrs, i.e. the silyl group of 61 migrates from carbon to nitrogen and the lithinm salt of an aUyl anion 63 is produced (equation 22) . 

Bis(organosilyl) peroxides are prepared by nucleophilic substitution reactions of hydrogen peroxide with chlorosilanes in the presence of base . Thus, bis(triorganosilyl) peroxide has been prepared from the reaction of 98% hydrogen peroxide and chlorosilane with ammonia as an HCl acceptor (equation 3). Bis(triphenylsilyl) peroxide 2 can also be prepared by the reaction of hydrogen peroxide and triphenyl silylamine (equation 4). 

Interesting variations of these reactions are observed when the a-silylamine donor funtion is tethered to an enone. For example, the intramolecular ET reaction of 143 results in two divergent cyclizations. Methanol assists the cleavage of the C—Si bond the resulting biradical anion 146 couples protonation and tautomer-ization then leads to 147. In acetonitrile, on the other hand, transfer of an a proton to the enone radical anion function forms biradical 144 coupling and tautomer-ization then generates 145. " ... 

Silylamines. The reaction of SiH3 and SiH3SiH2-halides with ammonia or various primary or... 

Further insertion reactions are worth mentioning. Trans-2-TMS-styrene (63) and triethylvinylsilane (61a) form with 14 the corresponding bis-silylamines trans-2-... 

Reductive-trimethylsilylation of formamides, using trimethylsilyl chloride and lithium in tetrahydrofurane lead to complex mixtures of O- and N-substituted derivatives that depend upon the conditions of the reaction and the substituents at nitrogen. However, in the presence of triethylamine, the reaction is oriented toward the unique formation of the a-silylamine. In general, the yields are moderate.185... 

The influence of steric factors was thoroughly studied in the reaction of Ln(btsa)3 with the alcohol tritox-H. While the reaction takes place with larger lanthanides like neodymium to yield the homoleptic alkoxide complexes (Eq. 18) [264], the analogous reaction does not work with smaller metals like yttrium and thulium (Eq. 19). However, variation of the reaction conditions to a stoichiometric solid reaction yielded a fully exchanged product along with an unexpected and unusual silylamine degradation [265] (Eq. 20). This degradation reaction seems to be sterically forced and points out N-Si bond disruptions and C-Si bond formations under mild conditions [114]. 

---