New azasilatranes: synthesis and substitution reactions

Abstract

The syntheses of new azasilatranes XSi(NRCH2CH2)3N (R = H, X = OEt (2f), OPh (2g); R = Me, X = H (8a), OEt (8b); R = SiMe3, X = H (9a)) via condensation reactions of tetraamines N(CH2CH2NHR)3 and substituted tris(dimethylamino)silanes, XSi(NMe2)3, are described. In the case of 2g, the required silane PhOSi(NMe2)3 was generated in situ from the reaction of PhOH and Si(NMe2)4. The chloroazasilatrane, 2h (R = H, X = Cl), whose synthesis was not feasible by the above method, was obtained by reaction of hydroazasilatrane, 2a (R = H, X = H) (V) with CCl4 in the presence of a platinum or palladium catalyst. Reaction of azasilatranes 2a and 2f with ClSiMe2R' (R' = H, Me, Ph) in the presence of triethylamine affords the silyl-substituted azasilatranes XSi(N(SiMe2R')CH2CH2)3N (X = H, R' = H (9b), Me (9a), Ph (9c); X = OEt, R' = H (14a)) and XSi(N(SiMe2R')CH2CH2)2NHCH2CH2N (X = OEt; R' = Me (14b), Ph (14d)), respectively, while no reaction was observed between either 2a or 2f and ClSiMe2-t-Bu. The new azasilatranes are characterized by 1H, 13C, and 29Si NMR spectroscopy, by high-resolution mass spectroscopy, and by an x-ray crystal structure determination in the case of 8b.