Cleavage of C–Si bond by intramolecular nucleophilic attack: lithiation-promoted formation of siloles from 1-bromo-4-trisubstituted silyl-1,3-butadiene derivatives

Lithiation of 1-bromo-4-trisubstituted silyl-1,3-butadiene derivatives with t-BuLi afforded substituted siloles in high yields. Cleavage of one of the three C–Si bonds took place via intramolecular nucleophilic substitution. Selective cleavage was observed when the silyl group possessed different substituents. Results showed that vinyl and phenyl substituents on Si were substituted much more easily than methyl groups, whilst a methyl group was exclusively deleted from an i-Pr–SiMe2 moiety.