Insertions‐, Isomerisierungs‐ und Cycloadditions‐Reaktionen lithiierter Aminofluorsilane

Abstract

Insertion, Isomerization, and Cycloaddition Reactions of Lithiated Aminofluorosilanes*The lithium derivative 2 of (di‐tert‐butylfluorosilyl)(fluorodi‐isopropylsilyl)amine (1) reacts with benzoyl chloride to form the imines 3I and 3II in an insertion reaction. LiF elimination from 2 leads to the cyclodisilazane [(CMe3)2SiFN—Si(CHMe2)2]2 (4). The fluorine atom of the SiF(CHMe2) group in 1 can be substituted by means of LiOSiMe3 to yield 5. The lithium derivative of 5 (6) is a dimer with very short Li—F distances. The lithium derivative 6 reacts with benzaldehyde in a [2 + 2] cycloaddition to give an (SiNCO) four‐membered ring compound (7), which thermally decomposes to yield the imine 8 and a cyclosiloxane, A fluorine/chlorine exchange is observed when Me3SiCl is added to the lithium derivative 6. The resulting unstable lithium derivative of an aminochlorosilane eliminates LiCl to form the cylcodisilazane 9. According to a crystal structure determination the formation of 9 involves isomerization of the intermediate iminosilane followed by dimerization.