Synthesis of aminotri- and aminotetrasilanes by cross-coupling of aminochlorosilanes with chlorotrimethylsilane

We studied the reductive coupling of aminochlorosilanes and chlorotrimethyl silane by lithium in tetrahydrofuran. Cross-coupling was observed in the ca se of diaminodichlorosilanes 7 or aminotrichlorosilanes 8 and allows a dire ct access to 2,2-diamino-hexamethyltrisilanes 9 and amino (tristrimethylsil yl)silanes 10. Me2Si(iPr(2)N)Cl 3 reacts instead preferentially to the symm etric diaminodisilane 6. Bulkier diamino (chloro)methylsilanes 5 did not un dergo the coupling reaction. The cross-coupled aminodi-, -tri- and tetrasil anes are useful starting compounds for other functionally substituted oligo silanes, as was shown by reaction of 9 with HX (X = CI, By, I) to Il and th e synthesis of the heterocyclic trisilanes 9d and 9f using 11a The molecula r structure of [(iPr(2)N)(2)SiH](2) 2a is discussed. NMR data including (1) J(SiSi) coupling constants are given. (C) 1999 John Wiley & Sons, Inc.