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

Abstract

We studied the reductive coupling of aminochlorosilanes and chlorotrimethylsilane by lithium in tetrahydrofuran. Cross-coupling was observed in the case of diaminodichlorosilanes 7 or aminotrichlorosilanes 8 and allows a direct access to 2,2-diamino-hexamethyltrisilanes 9 and amino(tristrimethylsilyl)silanes 10. Me2Si(iPr2N)Cl 3 reacts instead preferentially to the symmetric diaminodisilane 6. Bulkier diamino(chloro)methylsilanes 5 did not undergo the coupling reaction. The cross-coupled aminodi-, -tri- and tetrasilanes are useful starting compounds for other functionally substituted oligosilanes, as was shown by reaction of 9 with HX (X=Cl, Br, I) to 11 and the synthesis of the heterocyclic trisilanes 9d and 9f using 11a. The molecular structure of [(iPr2N)2SiH]2 2a is discussed. NMR data including 1JSiSi coupling constants are given. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10:605–614, 1999