Generation and Reactions of an Overcrowded Diaryldilithiosilane

Exhaustive reduction of dibromo(2,6-diisopropylphenyl){2,4,6-tris[bis(trimethylsilyl)methyl]phenyl}silane with excess amount of lithium naphthalenide (more than 4 molar amounts) in tetrahydrofuran at -78 °C gave the corresponding dilithiosilane, the effective formation of which was confirmed by the trapping experiments with a variety of electrophiles. The diaryldilithiosilane thus generated was found to be stable at -78 °C but undergo an intramolecular proton abstraction to give the lithium-migrated dilithiosilane.