Influences of steric factors on the reactivity and structure of diorganoalkoxysilylamides

Abstract

The combination of an alkoxy and an amino function combined in one silane is rarely found due to the difficult synthesis and isolation.[1] However, this combination offers unique opportunities to investigate the influence of steric requirements or the size of a metal on the structure or reactivity of alkoxysilylamides towards electrophiles by varying the metallating reagent (n-butyllithium or di-n-butylmagnesium) or the organo group on the amino function. For this purpose, we synthesized two alkoxyaminosilanes with acidic NH units that can be metalated. On the one hand, the tert-butylamino-substituted (tert-butylamino)-methoxydiphenylsilane (1) and on the other hand the isopropylamino-substituted methoxydiphenyl(isopropylamino)silane (2). The resulting structures showed an interesting interrelation between the Si–O or Si–N bond lengths and the strength of the coordinative bond to the corresponding metal cation (lithium or magnesium).