o-(Fluorodimethylsilyl)phenyllithium as a Versatile Reagent for Preparation of Unsymmetrical, Silicon-Functionalized o-Disilylbenzenes

o -(Fluorodimethylsilyl)phenyllithium ( 1 ) was prepared by bromine−lithium exchange between o -C 6 H 4 (SiMe 2 F)Br ( 2 ) and t -BuLi in Et 2 O at −78 °C. The electrophilic Si−F functionality in 1 is not attacked by the nucleophilic aryllithium moiety at that temperature. 7 Li, 19 F, and 29 Si NMR analyses supported by DFT calculations suggested that the structure of 1 involves an intramolecular coordination of the fluorine substituent to the lithium atom. Reactions of 1 with halosilanes produced unsymmetrical, silicon-halogenated o -disilylbenzenes 4 .